US Open · SF · Hard · 11 Sep 2015
Serena Williams v Roberta Vinci
93–85 in points · Roberta Vinci won
Why it went the way it did
Serena Williams won 4.1 more points than Roberta Vinci relative to what the serve alone predicted. Roberta Vinci's biggest leaks: slice shot selection −5.8, return shot selection −3.4, serve 1st execution −2.3.
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.
| Shot | Serena Williams | Roberta Vinci | ||||||
|---|---|---|---|---|---|---|---|---|
| Dir | Sel | Exec | Total | Dir | Sel | Exec | Total | |
| Serve 1st | +0.7 | ±0.0 | +6.2 | +6.9 | +0.5 | ±0.0 | −2.3 | −1.8 |
| Serve 2nd | −0.1 | ±0.0 | +0.4 | +0.3 | −0.1 | ±0.0 | +1.2 | +1.1 |
| Return | +0.3 | +1.4 | +2.3 | +4.1 | −0.4 | −3.4 | +0.3 | −3.4 |
| Forehand | +0.3 | +2.1 | +1.1 | +3.5 | +0.5 | +3.0 | +3.0 | +6.5 |
| Backhand | +1.2 | −0.4 | −7.7 | −6.9 | +0.2 | +0.4 | −2.3 | −1.7 |
| Slice | ±0.0 | −0.7 | −0.4 | −1.2 | +0.5 | −5.8 | +3.0 | −2.3 |
| Net | +0.3 | +1.6 | −2.4 | −0.6 | +0.3 | +0.1 | +1.9 | +2.4 |
| Touch | +0.1 | −0.7 | −0.4 | −1.0 | +0.1 | −1.2 | +1.4 | +0.2 |
| All shots | +2.6 | +3.3 | −0.7 | +5.2 | +1.6 | −6.9 | +6.3 | +1.0 |
Set by set
| Set | Serena Williams | Roberta Vinci | Net, Serena | |
|---|---|---|---|---|
| 1 | +4.5 | −1.8 | +6.3 | |
| 2 | +2.8 | +2.3 | +0.5 | |
| 3 | −2.1 | +0.6 | −2.7 |
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
| Set | Wide | Body | T |
|---|---|---|---|
| 1 | 57% 75% | – | 43% 50% |
| 2 | 37% 60% | 4% 0% | 59% 81% |
| 3 | 48% 56% | 3% 0% | 48% 63% |
Set to set +2.10 per 100 first serves in sets 2+
Within sets +0.52 per 100 first serves, every two to three service games
Roberta Vinci serving
| Set | Wide | Body | T |
|---|---|---|---|
| 1 | 52% 38% | – | 48% 42% |
| 2 | 26% 56% | 9% 67% | 66% 70% |
| 3 | 50% 73% | 7% 50% | 43% 62% |
Set to set +0.50 per 100 first serves in sets 2+
Within sets +1.75 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
5.6 points left on the table across 285 shots 1.97 per 100 shots
- Rally, shots 5–8: slice to your backhand side, you at net hit BH volley through the middle ×1; BH volley down the line rates higher · 0.30 pts
- Rally, shots 5–8: slice to your middle hit FH through the middle ×2; FH crosscourt rates higher · 0.26 pts
- Return of a 2nd serve, T, ad court hit FH through the middle ×3; FH inside-in rates higher · 0.25 pts
- Return of a 2nd serve, T, deuce court hit BH through the middle + approach ×1; BH crosscourt + approach rates higher · 0.22 pts
Roberta Vinci
7.3 points left on the table across 260 shots 2.80 per 100 shots
- Rally, shots 5–8: drive to your backhand side hit BH slice through the middle ×15; BH slice crosscourt rates higher · 0.90 pts
- Serve +1: deep return to your middle hit FH through the middle ×7; FH crosscourt rates higher · 0.42 pts
- Return of a 2nd serve, T, ad court hit FH through the middle ×4; FH inside-in rates higher · 0.33 pts
- Rally, shots 5–8: drive to your forehand side hit FH through the middle ×5; FH crosscourt rates higher · 0.27 pts