When the Tampa Bay Buccaneers and Tom Brady walloped the Kansas City Chiefs to earn Brady his seventh Super Bowl ring, it prompted a series of 'Is Brady the GOAT of all GOATs?' conversations. Most of those greatest-of-all-time discussions ended, or should have, upon remembrance that Serena Williams exists.

• Serena Williams Net Worth
• Venus Williams Boyfriend

Like Brady, Williams has the rings and the longevity. Her 23 Grand Slam titles are more than anyone else's in the sport's Open era -- she even won the 2017 Australian Open while pregnant -- and she has won at least one Slam in 14 different years.

Feb 18, 2021 Being Serena is a 2018 documentary series chronicling Serena Williams during her pregnancy, motherhood, marriage and return to tennis. It was a seminal period in her storied career, as well as for. Latest sports news and live scores from Yahoo Sports UK. Complete sport coverage with football results, cricket scores, F1, golf, rugby, tennis and more. Serena Williams was knocked out of the Australian Open in the semi-finals by Naomi Osaka on Thursday, ending her latest bid to match Margaret Court's record of 24 Grand Slam singles titles. Feb 15, 2021 Meantime, in addition to Serena’s 23 major titles and Venus Williams’ seven, two other American women have won Grand Slam titles in recent years, Kenin and Sloane Stephens (2017 U.S.

But she has dominated at a consistent level that Brady and other GOAT of GOATs candidates struggle to match. While Brady was named the NFL's most valuable player and named first-team All-Pro three times each, Williams has reached No. 1 in the WTA rankings in parts of 10 different years. At one point, she spent 186 consecutive weeks at No. 1.

To the extent that age has taken effect, both the 43-year-old Brady and the 39-year-old Williams have been forced to adapt their respective games. Williams faces Simona Halep on Tuesday (3 a.m. ET, ESPN2/ESPN App) in the 2021 Australian Open quarterfinals, and while she's 9-2 all time against Halep and 6-0 on hard courts, she's only 1-1 since her 2018 return to the tour. It's worth discussing just how her game has changed and what new strengths and weaknesses have formed.

First, let's walk back through Williams' career trajectory.

Williams' career has been defined by steady quality combined with bursts of dominance. Most of her Grand Slam titles have come in such bursts -- five titles in six Slams in 2002-03, five in eight from 2008 to '10, four in six in 2012-13, then four in a row from 2014-15 -- but between explosions and occasional injuries, she has still been a force, putting together a 0.794 win percentage in Slams she didn't win, equivalent to a quarterfinal appearance like the one she has put together so far in Melbourne.

Since her return at the 2018 French Open, her Slam win percentage is 0.849. She has reached four finals and made the semifinals at last fall's US Open. She remains a steady contender. If she does win her 24th Slam, it will be with a slightly different game.

To look at how Williams' game has changed, we'll once again lean on the data created by Tennis Abstract's Match Charting Project, as we recently did in looking at Novak Djokovic's standout traits. Jeff Sackmann and a host of volunteers have charted more than 8,500 matches and 5 million points, creating layers of extra data about serves, returns, shot placement and tendencies and allowing us to get a much better idea about what makes certain players unique.

In this case, charting data can allow us to look at the same player over different periods of time.

The Charting Project has captured 209 Williams matches through the years, from her second-round loss to sister Venus Williams at the 1998 Australian Open to last week's win over Laura Siegemund in the first round. While there is a larger sample of matches from the past decade or so, by separating Williams' charted matches into three buckets -- 1999 to 2011, 2012-17 (her most concentrated run of dominance) and 2018-present -- we can take note of what has changed through the years.

Let's start with the serve

Williams' serve has always been one of her biggest strengths, and during her 2012-17 run, in which she won 10 Slams, three WTA Finals and 12 1,000-level events, it was otherworldly.

These days, it's merely awesome. She appears to have taken a little bit of sting out of it in the name of better accuracy.

Over the 52 weeks before the Australian Open, across all matches (not only those charted), Williams' serve remained a force, ranking first among the WTA's top-60 players with a 12% ace percentage (Naomi Osaka was second at 9%) and second behind Osaka in first-serve win percentage (74%). She ranked a mortal 18th in second-serve win percentage (49%), however.

As seen above, Williams' second serve has never been a particular strength. Even in the most dominant point of her career, her second-serve win percentage was slightly under 50% in charted matches. And these stats have played out in similar fashion through four matches in Melbourne: She has recorded aces 11% of the time, and her first-serve win percentage is a stellar 80%, but she has won only 43% of her second-serve points, 37% in her last two matches.

Her first serve was particularly wayward when she dropped a 6-2 set to Aryna Sabalenka in the fourth round -- she landed just 12 of 33 first serves (36%) and won just five of 21 second-serve points (24%). If her first serve isn't accurate, things could become dicey against Halep, who headed into the Australian Open ranked fourth in win percentage on second-serve return points (61%).

It might do Williams some good to break tendencies against Halep, who broke her four times in their last meeting, a straight-sets romp in the 2019 Wimbledon final. You typically know where Williams is going to serve:

• On first serves to the deuce court, she has gone wide 57% of the time since 2018. (Average across all women's charting data from 1999 to present: 42%).

• On first serves to the ad court, she has gone up the T 56% of the time (40%).

• On second serves to the deuce court, she has gone to the body 63% of the time (46%).

• On second serves to the ad court, she goes wide 50% of the time (37%).

These tendencies have shifted a bit in recent times, particularly on the second serve -- she used to vary her deuce court serves a lot more while going wide on ad courts more frequently -- but she has always held clear tendencies. It works out most of the time, but Halep is an elite returner against both first and second serve. She broke Williams three times in their 2019 Australian Open encounter, too.

Of course, Williams broke five times in that match and won in three sets.

Her returns are getting deeper

Williams doesn't dominate quite as many points as she used to, but she has figured out new ways to establish potential control anyway. This is most evident in return data.

Sackmann's charts log return depth as either shallow (inside the service line), deep (beyond the service line) or very deep (closer to the baseline than the service line). Since 1999, 29.5% of all returns in play have been logged as 'very deep,' and while Williams used to focus more on power than depth (only 22% of her returns were 'very deep' in the 1999-2011 sample), that percentage has risen to 32% since 2018. She lands her forehand in this range 34% of the time, and against Siegemund she was very deep on 39% of her returns.

Granted, hitting outright winners trumps everything. She won 42% of first-serve return points in the 2012-17 charting sample, and that average has been only 35% since 2018. In all matches in the 52 weeks before the Australian Open, she won only 43% of all return points (31st among top-60 players), 34% against first serves (52nd).

Her return has been a revelation in Melbourne, however: she has won 50% of return points, 46% against first serves. She has broken 19 times in four matches, winning 54% of break points.

It's hard to generate offense against depth, and while Williams doesn't hit as many winners these days, she does force more errors:

• On points with 4-6 shots, she's winning 16% of points via forced error (up from 12% in 2012-17), 18% on returns. In all, she's winning more rallies in this range than ever before: 51%, slightly ahead of her 2012-17 form.

• On points with 7-9 shots, she's winning 13% of points via forced error (up from 11%). She's winning far more of these rallies than ever -- 57%, up from 53% from 2012-17 and 50% from 1999-2011.

• On points with 10+ shots, she's winning 13% of points via forced error (up from 12%), though her overall win percentage in these points (43%) is the lowest of these ranges.

Infosys, which provides data for the Australian Open, logs rallies slightly differently, but she's winning 59% of rallies lasting between 0-4 shots and 51% of those thereafter. Her ability to defend and hit with depth allowed her to buy time against Sabalenka while her serve was struggling, and it could serve her well moving forward, too, not only at the Australian Open but throughout 2021.

Williams has overachieved projections thus far at the Australian Open; Tennis Abstract's ELO rankings marked Sabalenka as a solid favorite in their fourth-round matchup, just as they favor Halep (67% win probability) in the quarters. Caesars by William Hill, on the other hand, sets Williams' betting odds at -140, equivalent to a 58% chance of victory.

Odds haven't always applied to Williams' career, though. She has won 10 Slams since her 30th birthday -- Steffi Graf, Chris Evert and Martina Navratilova combined for five such titles in their 30s -- and she's still playing at a top-10 level just seven months from her 40s. And if she continues to return and defend as she has in Australia, she will remain a contender for Slam No. 24 throughout 2021.

Being Serena is a 2018 documentary series chronicling Serena Williams during her pregnancy, motherhood, marriage and return to tennis. It was a seminal period in her storied career, as well as for women’s tennis.

A camera crew has been following the American superstar at the ongoing Australian Open too, presumably for a similar series. But even with all-access and intimate glimpse into her life, there is no way anyone can know what it is like being Serena.

On the tennis court, like in the record books, Serena stands alone.

This sporting solitude is particularly put in starker contrast after shattering defeats. Her heartbreaking loss to Naomi Osaka in the Australian Open 2021 semi-final and subsequent tearful exit from the press conference highlighted yet again the emotional rollercoaster she has to ride alone.

How could anyone else know what it is to win 23 Grand Slam singles titles in the Open era? How can anyone feel what it’s like to win a Major while eight weeks pregnant? How could anyone understand what it is to get yourself physically ready to play top-flight tennis and reach Slam finals less than a year after giving birth and undergoing life-saving surgery? How can anyone empathise with losing four straight finals after 23 wins?

Serena Williams Net Worth

No one can because no other tennis player has come close to achieving what she has or risen from adversity the way she has. For a player as successful and competitive, to fall short again and again and again, after battling all the odds to return to the highest level with a baby in tow, must be unimaginably difficult.

The 39-year-old has gotten up after every single blow, but on Thursday it felt like she was spent when she broke down during the press conference. The trigger was a question about saying farewell because she held her hand to her heart acknowledging the crowd. On the next one about her unforced error count, she teared up saying “I don’t know. I’m done,” and left the room.

She had been gracious on the court, hugging Osaka and thanking the fans, but off it, her resolve crumbled in that instant.

She had spent two decades in the spotlight and given hundreds of similar press conferences. But now, every loss is pegged as a goodbye, every gesture analysed for hidden meaning and it cannot be easy to answer the same questions or indeed enjoy playing.

A familiar story in big matches

Logically speaking, a 39-year-old who has won just the one WTA title in the last three years losing to a 23-year-old on an unbeaten streak which includes the last hard-court Grand Slam is no upset. In fact, Osaka was expected to win this match. She is 16 years younger and saved match points with ease two rounds back.

Why then did this defeat sting so much more? She has lost to the Japanese player – who considers Serena her idol – before, in the controversy-marred US Open final in 2018.

But that was before the worrying big-match anxiety of the American was known. In the two years since, it has become clear that this is a different Serena. A Serena who struggles in the kind of big points she used to win with a single shot, who cannot close out matches she once made a habit of dominating. Make no mistake, the 39-year-old is still a solid, hungry player who makes deep runs and challenges the best. But she is no longer the intimidating opponent she used to be.

Consider these two stats:

Serena Williams has reached a Grand Slam final for 13 straight seasons (from 2007 to 2019) including the year she gave birth. In her 23-year long career, she has failed to reach a Major semi-final in only two years – 1998, when she debuted and 2006 when she played only two Slams.

Yet, she has lost the six big (four finals, two semis) matches she has played since her return with all but one – the US Open semi-final against Victoria Azarenka – being straight sets

Serena's final losses

She has a total of 10 runner up trophies at Slams and four of them have come in the last three years. Crucially, the pattern in all these losses has been similar: a spate of unforced errors putting undue pressure on her normally powerful serve and a crippling inability to “make a shot” – as she yelled in the match against Osaka.

In matches like these, the anguish transcends the screen. For fans, some of whom this writer has spoken to, it hurts to watch her evident struggles. There was a time her presence was intimidating as she could hit out any player in the world, but she has now lost that edge even as her hunger remains the same. It’s not unlike what is happening with her sister and oldest supporter Venus Williams. But in Serena’s case, the strenuous effort is so much more visible and visceral.

Serena’s failing powers

Yes, she has lost early in almost every tournament since her return, but she always found a way to raise her level at Slams and put herself in a position to win the elusive record-equalling 24th title only to stumble at the last hurdle.

Yes, she has come up against some of the best players in the Major finals: old foe Angelique Kerber and the uber-consistent Simona Halep at Wimbledon, big-hitting young guns Osaka and Bianca Andreescu. But she has beaten the same Halep twice at the Australian Open and Osaka at the Rogers Cup in 2019.

Where then does the block lie?

Can it be the pressure of tying with Margaret Court’s overall record? Of course, she has already faced that, when all anyone could talk about was breaking Steffi Graf’s Open era record of 22.

Can it be the physical toll at the business end of a tournament? As a mother in her late 30s, possibly, but what then of one-week long Premier Tournaments?

Can it be a mental block in the big matches despite having two decades worth of experience at the level and more trophies than she has room for?

Venus Williams Boyfriend

No one seems to know this, not even Serena herself when asked in numerous interactions.

But here is what we know as tennis watchers. Reconciling ourselves to Serena’s failing power is not easy given her dominance spanned two decades and generations of players. But what is easy is respecting her will to compete and the effort she puts in every single time. That’s the prism Serena should be seen in 2021.

As we saw in Melbourne, she still belongs at this level.

There are days she looks her vintage self, like against Halep in the quarter-final, and raises hope. There are days when she slugs it out, like in the fourth-round clash against Aryna Sabalenka, and it gives reason to keep fighting. Then there are days when she is a shadow of the player she was, like against Osaka in the semi-final.

But with all these days combined, Serena keeps getting up every time she stumbles and moves to the next fight – the basics of any sporting story, right? That she is already the record holder in women’s tennis makes this gruelling effort extraordinary. Just like the life of Serena Jameka Williams.