RallyIQ

Monterrey · QF · Hard · 6 Mar 2020

Rebecca Peterson v Arantxa Rus

34–56 in points · Arantxa Rus won

Why it went the way it did

Arantxa Rus won 10.6 more points than Rebecca Peterson relative to what the serve alone predicted. Rebecca Peterson's biggest leaks: serve 2nd execution −1.1, backhand execution −0.8, forehand direction choices −0.8.

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.

ShotRebecca PetersonArantxa Rus
DirSelExecTotalDirSelExecTotal
Serve 1st −0.4 ±0.0 −0.3 −0.7 −0.4 ±0.0 +1.5 +1.1
Serve 2nd −0.1 ±0.0 −1.1 −1.2 ±0.0 ±0.0 ±0.0 ±0.0
Return −0.2 +0.5 −0.8 −0.5 −0.3 +0.2 +0.7 +0.6
Forehand −0.8 +1.5 −0.6 +0.1 −1.7 +1.1 +4.4 +3.8
Backhand −0.1 +0.1 −0.8 −0.8 −0.6 +0.5 +2.0 +2.0
Slice ±0.0 −0.5 −0.2 −0.6 ±0.0 −0.4 −0.4 −0.7
Touch ±0.0 −0.2 +0.1 −0.1 ±0.0 ±0.0 ±0.0 ±0.0
All shots −1.5+1.4 −3.8−3.9 −2.9+1.4 +8.1+6.7

Set by set

SetRebecca PetersonArantxa RusNet, Rebecca
1−3.2+3.6 −6.7
2−0.7+3.1 −3.8

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.

Rebecca Peterson serving

SetWideBodyT
1 27% 29% 42% 27% 31% 75%
2 26% 40% 37% 57% 37% 43%

Within sets −0.44 per 100 first serves, every two to three service games

Arantxa Rus serving

SetWideBodyT
1 56% 89% 31% 40% 13% 100%
2 36% 80% 43% 42% 21% 83%

Within sets −0.37 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.

Rebecca Peterson

5.4 points left on the table across 199 shots 2.72 per 100 shots

  1. Rally, shots 5–8: drive to your middle hit FH through the middle ×14; FH crosscourt rates higher · 0.98 pts
  2. Serve +1: mid-depth return to your middle hit FH through the middle ×7; FH crosscourt rates higher · 0.59 pts
  3. Long rally, 9+: drive to your middle hit FH through the middle ×6; FH down the line rates higher · 0.42 pts
  4. Rally, shots 5–8: drive to your forehand side hit FH through the middle ×5; FH crosscourt rates higher · 0.27 pts

Arantxa Rus

7.1 points left on the table across 198 shots 3.60 per 100 shots

  1. Serve +1: mid-depth return to your middle hit FH through the middle ×7; FH crosscourt rates higher · 0.59 pts
  2. Rally, shots 5–8: drive to your backhand side hit BH through the middle ×13; BH crosscourt rates higher · 0.56 pts
  3. Return +1: drive to your forehand side hit FH through the middle ×7; FH crosscourt rates higher · 0.44 pts
  4. Rally, shots 5–8: drive to your forehand side hit FH through the middle ×7; FH crosscourt rates higher · 0.38 pts