Rome · R32 · Clay · 17 Sep 2020
Kiki Bertens v Polona Hercog
53–69 in points · Polona Hercog won
Why it went the way it did
Polona Hercog won 8.1 more points than Kiki Bertens relative to what the serve alone predicted. Kiki Bertens's biggest leaks: forehand execution −5.6, backhand execution −2.9, slice execution −2.1.
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 | Kiki Bertens | Polona Hercog | ||||||
|---|---|---|---|---|---|---|---|---|
| Dir | Sel | Exec | Total | Dir | Sel | Exec | Total | |
| Serve 1st | +0.4 | ±0.0 | −1.6 | −1.2 | ±0.0 | +0.1 | −0.6 | −0.5 |
| Serve 2nd | +0.2 | ±0.0 | +0.2 | +0.4 | ±0.0 | ±0.0 | −0.4 | −0.4 |
| Return | ±0.0 | −0.3 | +0.1 | −0.2 | +0.3 | −0.5 | +1.3 | +1.1 |
| Forehand | +0.3 | +3.0 | −5.6 | −2.4 | ±0.0 | +3.0 | −1.9 | +1.1 |
| Backhand | +0.3 | +0.8 | −2.9 | −1.7 | +0.1 | +0.6 | −1.2 | −0.5 |
| Slice | ±0.0 | −1.4 | −2.1 | −3.4 | +0.6 | −4.3 | −0.2 | −3.9 |
| Net | −0.4 | +0.3 | +0.8 | +0.8 | −0.2 | +0.1 | +0.2 | ±0.0 |
| Touch | −0.1 | ±0.0 | ±0.0 | −0.1 | +0.1 | +0.4 | +2.7 | +3.3 |
| All shots | +0.8 | +2.5 | −11.2 | −7.9 | +1.0 | −0.6 | −0.2 | +0.2 |
Set by set
| Set | Kiki Bertens | Polona Hercog | Net, Kiki | |
|---|---|---|---|---|
| 1 | −6.5 | −1.6 | −4.9 | |
| 2 | −1.4 | +1.8 | −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.
Kiki Bertens serving
| Set | Wide | Body | T |
|---|---|---|---|
| 1 | 59% 48% | 3% 0% | 38% 40% |
| 2 | 55% 42% | 14% 33% | 32% 86% |
Set to set −0.46 per 100 first serves in sets 2+
Within sets +0.22 per 100 first serves, every two to three service games
Polona Hercog serving
| Set | Wide | Body | T |
|---|---|---|---|
| 1 | 31% 70% | 25% 38% | 44% 57% |
| 2 | 44% 50% | 15% 75% | 41% 82% |
Set to set +1.70 per 100 first serves in sets 2+
Within sets −0.02 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.
Kiki Bertens
5.9 points left on the table across 247 shots 2.37 per 100 shots
- Rally, shots 5–8: drive to your backhand side hit BH through the middle ×8; BH crosscourt rates higher · 0.34 pts
- Rally, shots 5–8: drive to your middle, you at net hit FH volley through the middle ×1; FH volley crosscourt rates higher · 0.24 pts
- Long rally, 9+: drive to your middle, you at net hit FH volley through the middle ×1; FH volley crosscourt rates higher · 0.24 pts
- Return +1: drive to your forehand side hit FH through the middle + approach ×1; FH crosscourt + approach rates higher · 0.19 pts
Polona Hercog
5.9 points left on the table across 243 shots 2.44 per 100 shots
- Rally, shots 5–8: drive to your backhand side hit FH through the middle ×4; FH inside-in rates higher · 0.42 pts
- Return of a 2nd serve, body, deuce court hit FH through the middle ×5; FH down the line rates higher · 0.35 pts
- Rally, shots 5–8: lob to your middle, you at net hit Smash through the middle ×1; Smash crosscourt rates higher · 0.25 pts
- Rally, shots 5–8: drive to your backhand side hit FH inside-out ×8; FH inside-in rates higher · 0.25 pts