Iga Świątek's Grand Slam Problem
Opportunities, threats and flipping stacked odds.
Some big news hit the tennis world yesterday. As fate would have it, I had just finished writing an article about Iga Świątek when news of her one-month suspension for taking contaminated medication broke. Aside from putting her name more in the spotlight, this news shouldn’t have any bearing on what I had written so, without further ado, here is the article in full:
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Iga Świątek wins a lot of points. 56.0% of all points she played this season to be exact. That’s down from the 57.1% she won in 2023, but right alongside 55.9% from 2022. But what do these numbers mean? In the last 10 years there have been eight instances of a player playing at least 20 matches over the course of a season and winning at least 55% of the points. Three of these were the aforementioned seasons of Świątek. In fact, Iga is the only player that has done it in the last five years. The others to achieve this were Serena Williams (2015, 2016 and 2019), Victoria Azarenka (2016*) and Maria Sharapova (2015). Świątek’s last three seasons come in at 5th, 1st and 4th on this list respectively. Even going back 15 years, no players other than the four mentioned here have achieved this (you can add another 4 to Serena’s tally and one apiece to Azarenka and Sharapova in this timespan).
*Azarenka missed half of the 2016 season through pregnancy
Here’s how those numbers translate to matches won. Below is a graph showing every season played on the WTA Tour since 2010 where a player has won at least half of their points and matches. To avoid the bottom left corner getting too clogged, I’ve only included players that have been ranked inside the top 25 at some point in their career. Świątek’s last three seasons are highlighted along with her contemporaries for reference. As ever, data comes from tennisabstract.com.
Sabalenka, Gauff and Rybakina’s best seasons have been very, very good. But they pale in comparison to Świątek. She is in a world of her own in the top right of the graph. A spot that was occupied by Serena in the past, with only Azarenka managing to break in on the odd occasion.
So Iga Świątek wins a lot more points than everyone else right now. More points means more games. More games means more sets. More sets means more matches. More matches means more tournaments. She has led in each of these categories for the last three years. Comfortably so in most cases. More tournaments should mean more big tournaments, namely grand slams.
Świątek has picked up Roland Garros titles at a healthy clip since the tour returned after the COVID pandemic. However, compared to the rest of her results at the non-clay slams, the US Open win in 2022 stands out as a bit of an outlier. You might say it is obvious that she would perform better at Roland Garros than any of the other slams. After all, she wins more points on clay than she does on hard and grass. However, this is down to her ridiculous performance on clay which is an entirely different kind of elite. Świątek still won 55.2% of her hard court points this year. That was more than anyone else on tour. She also won the most in 2023. And 2022. A smaller sample size, granted, but when you combine the last three years, no player has won more points on grass either. With all that in mind you can be forgiven for thinking that one slam outside of France seems low.
So what is different at these non-clay slams? Here is a table comparing slam and regular tour-level matches in the last three years on hard and grass courts:
There’s a worrying amount of red across the board. A few numbers that immediately jump out are the 1st serve % (1stIn), 2nd serve points won (2nd%) and 1st serve return points won (v1st%). Making fewer 1st serves coupled with a less potent 2nd serve is not a winning formula. The 1st serve return is the biggest contributor to the overall total points won drop-off.
I think the most illuminating numbers here are the ones concerning break points. Świątek’s break point saved % drops off at an alarming rate, more than her serve points won would suggest. However, her break point converted % remains pretty consistent, despite the drop-off in return points won. Opportunity and threat are two sides of the same coin. By the same token that a break point on your opponent’s serve is an opportunity, a break point on your own serve is a threat. One way of looking at the break point numbers above is that on the biggest stages, Świątek reacts to opportunity the same as usual, but threat incites a different reaction entirely.
How common is a 1.8% drop-off in total points won? Let’s compare Świątek with some grand slam regulars. There are 29 players currently ranked inside the top 50 who have played at least 18 matches at these three slams going back to 2022 (in other words they have won at least as many matches as they have lost). Of these players, Świątek performs the worst at the slams compared to the rest of the tour-level matches. And it’s not even close:
The simple way to look at this graph is positive means a player plays better at the slams than usual, whereas negative is worse. The graph skews positive thanks in part to two thirds of these players facing easier, on average, opponents in their slam matches. That being said, the same applies for Świątek and she’s still winning nearly 2% fewer points at the slams. Of her eight losses at slams since 2022, Pegula at the US Open this year was her only opponent ranked inside the top 20. By no means a perfect measure but the average rank of her opponents in these eight losses is 35 compared to 14 outside of the slams.
An interesting comparison that jumps out is Sabalenka. Her ability to elevate her level from her already lofty standards helps explain why she’s been able to pick up three slam titles in the last couple of years. The gap to Świątek is incredible. Even if you loosen the criteria to top 100 players with a minimum of 10 matches played in this time span, only 3 out of 73 players perform worse in the slams relative to their usual standard than Świątek. Their current world rankings are 46, 97 and 98.
The notion that Iga Świątek performs worse than expected at the grand slams not called Roland Garros is backed up by the underlying numbers. But 54.4% of total points won is still very high compared to most players. The only player that has a higher percentage is Sabalenka herself (55.4%). However, that extra percentage point makes all the difference. Using the data from the first graph I plotted a trendline to determine expected match win % based on a player’s total points won. Here’s a table showing total points won for a few key milestones:
A player that wins 52.3% of their points would be expected, on average, to reach the 3rd round of any given slam. A player that wins 54.6% would be expected to reach the quarterfinal. 55.7% should translate in a final. Let that sink in: a ~1% increase can be the difference between a quarterfinal and a final. I think this does a good job of putting in perspective how costly Świątek’s 1.8% drop in points won really is. However, you can easily look at it in a more positive light. We know Świątek is capable of winning over 56% of her points normally. If she can get her differential up to -1.0% then suddenly she could be averaging a semifinal at each slam appearance outside of Roland Garros. If she can match the differential of Elise Mertens (next lowest on the list), we’re looking at regular finals. If she can get rid of the differential altogether, we can only wish the rest of the tour the best of luck.
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What Does it Take to Beat Iga Świątek?
To round out today’s article let’s have a look at the basic numbers that determine whether Świątek wins each match she plays, regardless of stage. Just how different is a Świątek win to a Świątek loss? Here is a look at the relationship between serve and return points won in all of her completed matches (clay included) dating back to 2022. Results are split by wins and losses.
If Iga fails to win 40% of her return points she needs to serve lights out. By the same token, if she’s having an off-day on serve she’s probably going to have to win over half of her return points. But that’s nothing groundbreaking. Let’s have a look at the serve and return separately. Here is the similar graph split by 1st and 2nd serve points:
If Świątek wins at least 70% of her first serve points (as she does in over half of her matches), her record is 120-0. If she doesn’t, it’s 74-28 (72.5%) The red dots that are quite high up in the centre of the graph serve as a note of caution that a good day on 2nd serve doesn’t matter nearly as much as a good day on 1st serve. Now for a look at the same graph but on return:
The immediate thing that jumps out is this: in the last three years, Świątek has a 150-1 record when she wins at least 37.5% of 1st serve return points. A player can’t have an off-day on serve and beat Świątek, unless their name is Jelena Ostapenko. I think this number is even more impressive than the one quoted for serve. The record on the other side of this imaginary 37.5% drops all the way to 44-27 (62.0%). More evidence for just how important Świątek’s 1st serve return can be found by comparing her points won in each category for wins and losses:
The 1st serve return numbers might suggest that Świątek struggles against big servers. Players that can neutralise her normally very effective return. But she does still have her fair share of losses against players that wouldn’t be considered big servers by any stretch.
Świątek’s overall drop in total points won in her losses (11.9%) is the largest of any player in the top 50. This goes to show just how dominant she is in her wins. A slight issue with looking at all the surfaces together though is that a player might have quite a different record on each surface. In the last three seasons Świątek has won 92.6% of her clay court matches compared to 85.4% on hard, for example. With more losses coming on hard courts, you would expect the return points to take more of a hit than the service points when everything is grouped together. However, the trend holds true when you isolate clay and hard courts. The number that always sticks out is the 1st serve return points won.
So we’ve established that despite her numbers, Iga Świątek is beatable. But just how can an opponent overturn the odds that are stacked against them? Well for starters, they almost certainly need to win 62.5% of their 1st serve points. That’s 5/8, nothing crazy for a half-decent server. Combine that with 37.5% of their 2nd serve points, or 3/8. How about return? Try winning 24% of the 1st serve return points and 37.5% of the 2nd serve return points. All those numbers might sound like they’ve been randomly cobbled together. But when opponents have met all of those criteria, that has accounted for 24 of Świątek’s 28 losses in the last three years (Świątek has won just six matches when all criteria are met).
In isolation, each of the numbers is very achievable. The key is putting it all together.
Appendix
Cover photo adapted from Hameltion, CC BY-SA 4.0, via Wikimedia Commons
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Abbreviations (use the tennisabstract naming convention)
SPW: Serve points won
1stIn: 1st serve %
1st%: 1st serve points won
2nd%: 2nd serve points won
BPSvd%: Break points saved
Hld%: Hold %
BPS-SPW: Break points saved minus serve points won
RPW: Return points won
v1st%: 1st serve return points won
v2nd%: 2nd serve return points won
BPConv%: Break points converted
Brk%: Break %
BPC-RPW: Break points converted minus return points won
TPW%: Total points won
Win%: Match win %