RallyIQ

Indian Wells · F · Hard · 17 Mar 2019

Angelique Kerber v Bianca Andreescu

94–100 in points · Bianca Andreescu won

Why it went the way it did

Bianca Andreescu won 3.1 more points than Angelique Kerber relative to what the serve alone predicted. Angelique Kerber's biggest leaks: slice shot selection −4.0, touch shot selection −2.1, forehand execution −1.0.

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.

ShotAngelique KerberBianca Andreescu
DirSelExecTotalDirSelExecTotal
Serve 1st −0.1 ±0.0 −0.8 −0.9 −0.2 ±0.0 −2.5 −2.7
Serve 2nd ±0.0 ±0.0 +0.6 +0.6 ±0.0 ±0.0 +0.4 +0.4
Return −0.1 −0.1 +2.1 +1.9 −0.6 +0.7 +0.5 +0.6
Forehand −0.8 +0.6 −1.0 −1.2 +0.3 +2.7 +6.5 +9.6
Backhand −0.6 −0.7 +0.2 −1.2 −0.5 +0.8 −1.4 −1.1
Slice −0.1 −4.0 +1.1 −3.0 −0.3 −5.9 −0.8 −7.1
Net −0.2 +0.1 −0.2 −0.2 −0.2 +1.0 −1.4 −0.6
Touch −0.1 −2.1 +0.9 −1.2 −0.1 −2.0 +0.2 −1.9
Other −0.1 −0.3 −0.2 −0.7 ±0.0 ±0.0 ±0.0 ±0.0
All shots −2.1−6.4 +2.7−5.9 −1.6−2.6 +1.4−2.8

Set by set

SetAngelique KerberBianca AndreescuNet, Angelique
1−3.1−0.2 −2.9
2−1.9−4.9 +3.0
3−0.9+2.3 −3.2

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.

Angelique Kerber serving

SetWideBodyT
1 50% 65% 26% 44% 24% 75%
2 51% 83% 14% 20% 34% 58%
3 55% 38% 28% 50% 17% 60%

Set to set +1.12 per 100 first serves in sets 2+

Within sets +0.49 per 100 first serves, every two to three service games

Bianca Andreescu serving

SetWideBodyT
1 41% 82% 22% 83% 37% 60%
2 37% 62% 20% 57% 43% 53%
3 44% 60% 29% 60% 26% 44%

Set to set +0.52 per 100 first serves in sets 2+

Within sets +0.18 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.

Angelique Kerber

13.6 points left on the table across 418 shots 3.26 per 100 shots

  1. Serve +1: mid-depth return to your middle hit BH through the middle ×11; BH crosscourt rates higher · 0.67 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 of a 2nd serve, wide, deuce court hit BH crosscourt ×4; BH inside-out rates higher · 0.51 pts
  4. Rally, shots 5–8: drive to your middle hit FH through the middle ×7; FH crosscourt rates higher · 0.49 pts

Bianca Andreescu

12.7 points left on the table across 444 shots 2.85 per 100 shots

  1. Return of a 1st serve, wide, ad court hit BH through the middle ×21; BH crosscourt rates higher · 0.61 pts
  2. Rally, shots 5–8: drive to your middle hit FH through the middle ×7; FH crosscourt rates higher · 0.49 pts
  3. Rally, shots 5–8: drive to your backhand side hit BH slice through the middle ×7; BH slice crosscourt rates higher · 0.42 pts
  4. Rally, shots 5–8: drive to your forehand side hit FH through the middle ×7; FH crosscourt rates higher · 0.38 pts