RallyIQ

US Open · F · Hard · 7 Sep 2024

Aryna Sabalenka v Jessica Pegula

88–79 in points · Aryna Sabalenka won

Why it went the way it did

Aryna Sabalenka won 4.7 more points than Jessica Pegula relative to what the serve alone predicted. Jessica Pegula's biggest leaks: forehand execution −2.9, slice shot selection −2.3, return shot selection −1.4.

Each shot moves its hitter's chance of winning the point. Those moves are split into direction choice, shot selection and execution, and summed here. Read both columns together: one player's gain is the other's loss.

ShotAryna SabalenkaJessica Pegula
DirSelExecTotalDirSelExecTotal
Serve 1st ±0.0 ±0.0 +0.2 +0.3 −0.9 ±0.0 +0.7 −0.2
Serve 2nd +0.1 ±0.0 −0.5 −0.5 ±0.0 ±0.0 −0.4 −0.4
Return +0.1 −1.1 +1.7 +0.8 −0.2 −1.4 +1.0 −0.5
Forehand +0.4 +2.0 +3.3 +5.7 −0.7 +1.9 −2.9 −1.7
Backhand +0.8 +0.9 −2.6 −0.9 −0.2 +0.8 +1.9 +2.5
Slice ±0.0 −3.3 −3.1 −6.4 −0.2 −2.3 ±0.0 −2.5
Net +0.4 +0.8 +2.4 +3.6 +0.1 ±0.0 +0.3 +0.4
Touch +0.1 +0.1 −1.0 −0.9 ±0.0 +0.2 −0.8 −0.5
All shots +1.9−0.5 +0.3+1.8 −2.1−0.7 −0.2−3.0

Set by set

SetAryna SabalenkaJessica PegulaNet, Aryna
1+0.1−0.5 +0.6
2+1.7−2.5 +4.2

Adaptation

First-serve direction mix set by set, with the share of points each direction won. The scores measure whether the server moved toward the directions that had been winning earlier in this match, set to set and every two to three service games, in points per 100 first serves. Read them as a habit, not a gain: across the tour, a direction's edge in early sets barely predicts the later ones. Whether the returner responded can't be told apart from noise within one match.

Aryna Sabalenka serving

SetWideBodyT
1 47% 52% 22% 45% 31% 60%
2 42% 64% 12% 0% 45% 73%

Set to set −2.60 per 100 first serves in sets 2+

Within sets −1.90 per 100 first serves, every two to three service games

Jessica Pegula serving

SetWideBodyT
1 30% 46% 44% 58% 26% 45%
2 31% 54% 43% 39% 26% 64%

Set to set +0.62 per 100 first serves in sets 2+

Within sets +0.14 per 100 first serves, every two to three service games

Counterfactual: the best direction every time

If each shot had gone in the direction that is usually worth most for that stroke and position, this is how many more points each player would expect to win. It's an upper bound: the best direction isn't always on, and the chart can't see the ball's pace or position.

Aryna Sabalenka

6.3 points left on the table across 290 shots 2.18 per 100 shots

  1. Rally, shots 5–8: drive to your backhand side, opponent at net, you at net hit BH volley through the middle ×1; BH volley crosscourt rates higher · 0.29 pts
  2. Rally, shots 5–8: drive to your backhand side hit BH slice through the middle ×4; BH slice crosscourt rates higher · 0.24 pts
  3. Rally, shots 5–8: drive to your backhand side hit BH through the middle ×5; BH crosscourt rates higher · 0.21 pts
  4. Return of a 1st serve, body, deuce court hit BH down the line ×5; BH through the middle rates higher · 0.21 pts

Jessica Pegula

8.2 points left on the table across 267 shots 3.06 per 100 shots

  1. Rally, shots 5–8: drive to your forehand side hit FH through the middle ×9; FH crosscourt rates higher · 0.49 pts
  2. Return of a 2nd serve, body, deuce court hit BH through the middle ×7; BH crosscourt rates higher · 0.32 pts
  3. Return +1: drive to your backhand side hit BH slice through the middle ×4; BH slice crosscourt rates higher · 0.26 pts
  4. Serve +1: mid-depth return to your middle hit BH through the middle ×4; BH crosscourt rates higher · 0.25 pts