RallyIQ

Indian Wells · R32 · Hard · 10 Mar 2019

Bianca Andreescu v Stefanie Voegele

56–31 in points · Bianca Andreescu won

Why it went the way it did

Bianca Andreescu won 12.6 more points than Stefanie Voegele relative to what the serve alone predicted. Stefanie Voegele's biggest leaks: return execution −4.3, forehand execution −2.6, serve 1st execution −1.4.

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.

ShotBianca AndreescuStefanie Voegele
DirSelExecTotalDirSelExecTotal
Serve 1st +0.1 ±0.0 +1.4 +1.4 +0.1 ±0.0 −1.4 −1.3
Serve 2nd ±0.0 ±0.0 +0.3 +0.3 ±0.0 ±0.0 +0.9 +0.9
Return −0.4 +0.4 +0.1 +0.1 +0.1 +0.3 −4.3 −3.9
Forehand −0.6 +1.3 −0.8 ±0.0 −0.4 +0.3 −2.6 −2.7
Backhand −0.2 +0.4 +1.3 +1.6 +0.1 −0.2 +1.3 +1.2
Slice +0.1 −1.1 −0.5 −1.6 +0.1 −1.0 −0.3 −1.3
Net +0.1 +0.4 +1.0 +1.5 ±0.0 ±0.0 −0.5 −0.5
Touch +0.1 −0.3 +2.3 +2.2 +0.1 −0.3 +0.7 +0.6
All shots −0.7+1.1 +5.2+5.6 +0.2−0.9 −6.2−7.0

Set by set

SetBianca AndreescuStefanie VoegeleNet, Bianca
1+0.6−5.0 +5.6
2+5.0−2.0 +6.9

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.

Bianca Andreescu serving

SetWideBodyT
1 38% 67% 8% 50% 54% 77%
2 32% 100% 21% 75% 47% 78%

Within sets −0.16 per 100 first serves, every two to three service games

Stefanie Voegele serving

SetWideBodyT
1 44% 38% – 56% 50%
2 46% 42% 23% 50% 31% 63%

Within sets +1.07 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.

Bianca Andreescu

4.5 points left on the table across 148 shots 3.04 per 100 shots

  1. Rally, shots 5–8: drive to your backhand side hit BH through the middle ×5; BH crosscourt rates higher · 0.21 pts
  2. Rally, shots 5–8: drive to your middle hit FH through the middle ×3; FH crosscourt rates higher · 0.21 pts
  3. Return of a 2nd serve, wide, ad court hit BH through the middle ×4; BH crosscourt rates higher · 0.19 pts
  4. Return +1: drive to your middle hit FH through the middle ×3; FH down the line rates higher · 0.19 pts

Stefanie Voegele

3.6 points left on the table across 139 shots 2.58 per 100 shots

  1. Rally, shots 5–8: drive to your middle hit FH through the middle ×4; FH crosscourt rates higher · 0.28 pts
  2. Long rally, 9+: drive to your middle hit FH through the middle ×3; FH down the line rates higher · 0.21 pts
  3. Serve +1: deep return to your middle hit BH down the line ×3; BH crosscourt rates higher · 0.21 pts
  4. Serve +1: short return to your middle hit FH through the middle ×2; FH down the line rates higher · 0.19 pts