RallyIQ

US Open · R16 · Hard · 4 Sep 2023

Ons Jabeur v Qinwen Zheng

47–66 in points · Qinwen Zheng won

Why it went the way it did

Qinwen Zheng won 10.9 more points than Ons Jabeur relative to what the serve alone predicted. Ons Jabeur's biggest leaks: forehand execution −2.1, serve 1st execution −1.7, return execution −1.7.

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.

ShotOns JabeurQinwen Zheng
DirSelExecTotalDirSelExecTotal
Serve 1st +0.4 ±0.0 −1.7 −1.3 +0.3 ±0.0 −1.2 −0.9
Serve 2nd +0.1 ±0.0 +0.6 +0.7 +0.1 ±0.0 −1.3 −1.2
Return −0.2 −1.0 −1.7 −2.9 ±0.0 −0.2 +2.2 +2.0
Forehand +0.4 +1.0 −2.1 −0.7 −0.3 +1.2 +1.8 +2.7
Backhand +0.4 +0.4 −1.5 −0.8 −0.2 +0.7 +0.9 +1.4
Slice ±0.0 −1.6 ±0.0 −1.6 −0.1 −2.0 −0.1 −2.2
Net +0.3 +0.1 −0.9 −0.5 +0.2 +0.4 −0.3 +0.3
Touch ±0.0 +0.1 −1.4 −1.3 −0.1 −0.2 +0.1 −0.2
Other ±0.0 −0.1 −0.4 −0.5 ±0.0 ±0.0 ±0.0 ±0.0
All shots +1.3−1.2 −9.1−9.0 −0.1−0.1 +2.2+1.9

Set by set

SetOns JabeurQinwen ZhengNet, Ons
1−5.1+1.2 −6.3
2−3.9+0.7 −4.6

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.

Ons Jabeur serving

SetWideBodyT
1 41% 18% 11% 67% 48% 54%
2 56% 50% 5% 50% 38% 40%

Within sets −0.27 per 100 first serves, every two to three service games

Qinwen Zheng serving

SetWideBodyT
1 57% 77% 4% 100% 39% 44%
2 33% 50% 8% 50% 58% 64%

Within sets −1.70 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.

Ons Jabeur

3.7 points left on the table across 178 shots 2.09 per 100 shots

  1. Return of a 2nd serve, wide, ad court hit BH through the middle + approach ×1; BH down the line + approach rates higher · 0.32 pts
  2. Serve +1: mid-depth return to your middle hit BH through the middle ×3; BH crosscourt rates higher · 0.18 pts
  3. Rally, shots 5–8: drive to your backhand side hit BH slice through the middle ×3; BH slice crosscourt rates higher · 0.18 pts
  4. Serve +1: mid-depth return to your middle hit FH through the middle ×2; FH crosscourt rates higher · 0.17 pts

Qinwen Zheng

5.0 points left on the table across 182 shots 2.77 per 100 shots

  1. Rally, shots 5–8: drive to your backhand side hit BH through the middle ×8; BH crosscourt rates higher · 0.34 pts
  2. Return +1: drive to your backhand side hit BH through the middle ×7; BH crosscourt rates higher · 0.33 pts
  3. Return of a 1st serve, wide, deuce court hit FH through the middle ×8; FH crosscourt rates higher · 0.20 pts
  4. Serve +1: mid-depth return to your middle hit FH through the middle ×2; FH down the line rates higher · 0.18 pts