RallyIQ

San Diego · QF · Hard · 26 Feb 2024

Donna Vekic v Katie Boulter

62–70 in points · Katie Boulter won

Why it went the way it did

Katie Boulter won 4.0 more points than Donna Vekic relative to what the serve alone predicted. Donna Vekic's biggest leaks: forehand execution −3.3, touch shot selection −2.1, serve 2nd execution −1.2.

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.

ShotDonna VekicKatie Boulter
DirSelExecTotalDirSelExecTotal
Serve 1st +0.1 ±0.0 +0.1 +0.2 −0.2 ±0.0 −1.3 −1.5
Serve 2nd +0.1 ±0.0 −1.2 −1.1 +0.1 ±0.0 −0.9 −0.9
Return −0.1 +0.1 −0.3 −0.3 −0.2 −0.3 +0.7 +0.2
Forehand −0.5 +1.1 −3.3 −2.8 +0.2 +1.0 −0.4 +0.7
Backhand −0.2 +0.5 +1.8 +2.0 −0.2 +0.1 +0.8 +0.6
Slice ±0.0 −0.9 +0.5 −0.4 ±0.0 −0.5 +0.5 ±0.0
Net ±0.0 +0.1 −0.8 −0.7 +0.2 +1.1 −1.1 +0.2
Touch +0.2 −2.1 +0.1 −1.8 ±0.0 −0.4 +0.2 −0.2
All shots −0.5−1.2 −3.1−4.9 −0.1+0.9 −1.7−0.9

Set by set

SetDonna VekicKatie BoulterNet, Donna
1−3.3−2.6 −0.7
2−1.6+1.8 −3.3

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.

Donna Vekic serving

SetWideBodyT
1 57% 59% 17% 20% 27% 75%
2 58% 43% 17% 50% 25% 56%

Set to set −0.92 per 100 first serves in sets 2+

Within sets +0.08 per 100 first serves, every two to three service games

Katie Boulter serving

SetWideBodyT
1 44% 50% 27% 82% 29% 50%
2 48% 67% 28% 43% 24% 50%

Set to set −0.75 per 100 first serves in sets 2+

Within sets +1.71 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.

Donna Vekic

6.1 points left on the table across 197 shots 3.08 per 100 shots

  1. Return of a 2nd serve, wide, deuce court hit FH through the middle ×5; FH inside-out rates higher · 0.57 pts
  2. Rally, shots 5–8: drive to your forehand side hit FH through the middle ×8; FH crosscourt rates higher · 0.43 pts
  3. Rally, shots 5–8: drive to your middle hit FH through the middle ×5; FH crosscourt rates higher · 0.35 pts
  4. Serve +1: mid-depth return to your middle hit FH through the middle ×4; FH crosscourt rates higher · 0.34 pts

Katie Boulter

5.4 points left on the table across 204 shots 2.66 per 100 shots

  1. Serve +1: mid-depth return to your middle hit FH through the middle ×4; FH crosscourt rates higher · 0.34 pts
  2. Rally, shots 5–8: drive to your middle hit BH through the middle ×7; BH crosscourt rates higher · 0.33 pts
  3. Rally, shots 5–8: drive to your forehand side hit FH through the middle ×5; FH crosscourt rates higher · 0.27 pts
  4. Rally, shots 5–8: lob to your middle, you at net hit Smash through the middle ×1; Smash crosscourt rates higher · 0.25 pts