RallyIQ

US Open · R16 · Hard · 1 Sep 2024

Qinwen Zheng v Donna Vekic

107–100 in points · Qinwen Zheng won

Why it went the way it did

Qinwen Zheng won 2.7 more points than Donna Vekic relative to what the serve alone predicted. Donna Vekic's biggest leaks: forehand execution −3.4, return execution −3.3, backhand execution −2.0.

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.

ShotQinwen ZhengDonna Vekic
DirSelExecTotalDirSelExecTotal
Serve 1st +0.2 ±0.0 +0.7 +0.8 +0.5 ±0.0 +1.1 +1.5
Serve 2nd +0.2 ±0.0 −0.2 −0.1 +0.1 ±0.0 −1.3 −1.2
Return −0.6 +0.1 −2.3 −2.8 +0.1 +0.4 −3.3 −2.8
Forehand +0.8 +2.2 −0.5 +2.5 −0.4 +2.6 −3.4 −1.1
Backhand −0.4 +0.2 −1.9 −2.1 −0.1 +1.0 −2.0 −1.1
Slice ±0.0 −2.5 +0.1 −2.4 +0.1 −1.1 −1.3 −2.3
Net +0.2 +1.1 −0.2 +1.1 −0.1 ±0.0 +0.6 +0.6
Touch +0.1 −0.1 +1.1 +1.1 +0.1 ±0.0 +1.6 +1.8
All shots +0.3+1.1 −3.2−1.8 +0.5+2.9 −7.9−4.5

Set by set

SetQinwen ZhengDonna VekicNet, Qinwen
1−1.1−1.5 +0.4
2−2.1+1.2 −3.3
3+1.3−4.3 +5.6

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.

Qinwen Zheng serving

SetWideBodyT
1 45% 63% 14% 83% 40% 76%
2 52% 45% 10% 50% 38% 69%
3 48% 67% 32% 63% 20% 80%

Set to set +0.43 per 100 first serves in sets 2+

Within sets +0.81 per 100 first serves, every two to three service games

Donna Vekic serving

SetWideBodyT
1 59% 63% 10% 75% 32% 85%
2 65% 60% 13% 75% 23% 71%
3 81% 48% 8% 50% 12% 33%

Set to set −1.66 per 100 first serves in sets 2+

Within sets −0.44 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.

Qinwen Zheng

7.8 points left on the table across 283 shots 2.75 per 100 shots

  1. Return of a 1st serve, wide, ad court hit BH down the line ×6; BH crosscourt rates higher · 0.58 pts
  2. Return of a 2nd serve, wide, deuce court hit FH through the middle ×4; FH inside-out rates higher · 0.45 pts
  3. Return of a 2nd serve, T, ad court hit FH through the middle ×4; FH inside-in rates higher · 0.33 pts
  4. Rally, shots 5–8: drive to your middle hit FH through the middle ×4; FH crosscourt rates higher · 0.28 pts

Donna Vekic

7.0 points left on the table across 295 shots 2.36 per 100 shots

  1. Rally, shots 5–8: drive to your middle hit FH through the middle ×6; FH crosscourt rates higher · 0.42 pts
  2. Rally, shots 5–8: drive to your forehand side hit FH through the middle ×7; FH crosscourt rates higher · 0.38 pts
  3. Rally, shots 5–8: drive to your backhand side hit BH through the middle ×8; BH crosscourt rates higher · 0.34 pts
  4. Return +1: drive to your forehand side hit FH through the middle ×5; FH crosscourt rates higher · 0.32 pts