RallyIQ

Zhengzhou · R32 · Hard · 10 Sep 2019

Bibiane Schoofs v Saisai Zheng

64–84 in points · Saisai Zheng won

Why it went the way it did

Saisai Zheng won 10.8 more points than Bibiane Schoofs relative to what the serve alone predicted. Bibiane Schoofs's biggest leaks: forehand execution −4.7, slice shot selection −3.6, net execution −3.2.

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.

ShotBibiane SchoofsSaisai Zheng
DirSelExecTotalDirSelExecTotal
Serve 1st −0.2 ±0.0 −0.4 −0.7 −0.4 +0.2 −0.7 −0.9
Serve 2nd ±0.0 ±0.0 −2.0 −2.0 ±0.0 ±0.0 +0.8 +0.8
Return −0.1 +0.3 +1.1 +1.3 −0.7 +0.5 +1.9 +1.8
Forehand +0.5 +3.6 −4.7 −0.6 −1.4 +3.0 +0.4 +1.9
Backhand −0.1 +1.3 −1.3 −0.1 −0.5 +2.2 −0.4 +1.2
Slice +0.4 −3.6 +0.1 −3.0 −0.4 −3.7 −0.7 −4.8
Net +0.1 +0.3 −3.2 −2.8 +0.1 +0.4 +0.5 +1.0
Touch +0.1 −2.3 −1.3 −3.6 −0.1 −2.9 +0.9 −2.1
Other −0.1 −0.3 ±0.0 −0.4 ±0.0 ±0.0 ±0.0 ±0.0
All shots +0.6−0.7 −11.7−11.9 −3.4−0.4 +2.7−1.0

Set by set

SetBibiane SchoofsSaisai ZhengNet, Bibiane
1−6.7−3.4 −3.2
2−5.2+2.4 −7.6

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.

Bibiane Schoofs serving

SetWideBodyT
1 50% 67% 25% 33% 25% 47%
2 44% 57% 31% 20% 25% 25%

Set to set −3.73 per 100 first serves in sets 2+

Within sets +0.72 per 100 first serves, every two to three service games

Saisai Zheng serving

SetWideBodyT
1 53% 58% 33% 56% 14% 71%
2 50% 73% 32% 71% 18% 100%

Set to set −0.69 per 100 first serves in sets 2+

Within sets −1.24 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.

Bibiane Schoofs

9.4 points left on the table across 385 shots 2.44 per 100 shots

  1. Rally, shots 5–8: drive to your forehand side hit FH through the middle ×7; FH crosscourt rates higher · 0.38 pts
  2. Rally, shots 5–8: drive to your middle hit FH through the middle ×5; FH crosscourt rates higher · 0.35 pts
  3. Return +1: drive to your middle hit FH through the middle ×5; FH down the line rates higher · 0.32 pts
  4. Rally, shots 5–8: drive to your backhand side hit BH through the middle ×7; BH crosscourt rates higher · 0.30 pts

Saisai Zheng

13.0 points left on the table across 385 shots 3.37 per 100 shots

  1. Rally, shots 5–8: drive to your forehand side hit FH through the middle ×12; FH crosscourt rates higher · 0.65 pts
  2. Rally, shots 5–8: drive to your middle hit FH through the middle ×9; FH crosscourt rates higher · 0.63 pts
  3. Serve +1: mid-depth return to your middle hit FH through the middle ×7; FH crosscourt rates higher · 0.59 pts
  4. Rally, shots 5–8: drive to your backhand side hit BH through the middle ×12; BH crosscourt rates higher · 0.52 pts