RallyIQ

Roland Garros · R64 · Clay · 2 Jun 2021

Serena Williams v Mihaela Buzarnescu

97–74 in points · Serena Williams won

Why it went the way it did

Serena Williams won 11.9 more points than Mihaela Buzarnescu relative to what the serve alone predicted. Mihaela Buzarnescu's biggest leaks: return execution −4.9, slice shot selection −3.3, serve 2nd 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.

ShotSerena WilliamsMihaela Buzarnescu
DirSelExecTotalDirSelExecTotal
Serve 1st +0.6 ±0.0 +1.2 +1.7 −0.4 ±0.0 −1.3 −1.7
Serve 2nd ±0.0 ±0.0 +1.0 +1.0 −0.1 ±0.0 −1.4 −1.5
Return −0.2 +0.9 −0.4 +0.3 −0.5 −1.3 −4.9 −6.6
Forehand +0.5 +1.5 +1.5 +3.5 +0.3 +2.0 +0.3 +2.7
Backhand +0.5 −0.2 −1.3 −1.1 +0.2 −0.1 +1.9 +2.0
Slice +0.1 −1.5 −1.0 −2.4 ±0.0 −3.3 −0.5 −3.7
Net ±0.0 +0.3 −0.6 −0.3 ±0.0 ±0.0 ±0.0 ±0.0
Touch −0.1 ±0.0 −0.2 −0.3 ±0.0 −0.3 −0.2 −0.5
All shots +1.4+1.0 +0.1+2.5 −0.4−3.0 −6.0−9.4

Set by set

SetSerena WilliamsMihaela BuzarnescuNet, Serena
1+1.3−5.4 +6.7
2−1.3−0.1 −1.2
3+2.5−4.0 +6.4

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.

Serena Williams serving

SetWideBodyT
1 43% 90% 13% 100% 43% 80%
2 44% 60% 3% 100% 53% 61%
3 48% 58% 4% 0% 48% 75%

Set to set −1.02 per 100 first serves in sets 2+

Within sets −0.20 per 100 first serves, every two to three service games

Mihaela Buzarnescu serving

SetWideBodyT
1 27% 57% 42% 64% 31% 50%
2 21% 75% 28% 64% 51% 60%
3 42% 70% 21% 0% 38% 22%

Set to set +0.33 per 100 first serves in sets 2+

Within sets −0.63 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.

Serena Williams

5.9 points left on the table across 291 shots 2.03 per 100 shots

  1. Return of a 2nd serve, body, ad court hit FH through the middle ×5; FH crosscourt rates higher · 0.31 pts
  2. Rally, shots 5–8: drive to your middle hit FH through the middle ×4; FH crosscourt rates higher · 0.28 pts
  3. Rally, shots 5–8: slice to your middle, you at net hit BH volley through the middle ×1; BH volley crosscourt rates higher · 0.23 pts
  4. Long rally, 9+: drive to your forehand side hit FH through the middle ×4; FH crosscourt rates higher · 0.22 pts

Mihaela Buzarnescu

8.2 points left on the table across 293 shots 2.80 per 100 shots

  1. Return of a 2nd serve, body, deuce court hit FH through the middle ×7; FH down the line rates higher · 0.49 pts
  2. Return of a 1st serve, T, deuce court hit FH down the line ×2; FH inside-out rates higher · 0.45 pts
  3. Return of a 1st serve, T, ad court hit BH slice through the middle ×4; BH slice crosscourt rates higher · 0.43 pts
  4. Rally, shots 5–8: drive to your backhand side hit BH through the middle ×9; BH crosscourt rates higher · 0.39 pts