RallyIQ

Stockholm · F · Hard · 17 Oct 2016

Jack Sock v Juan Martin Del Potro

38–60 in points · Juan Martin Del Potro won

Why it went the way it did

Juan Martin Del Potro won 12.7 more points than Jack Sock relative to what the serve alone predicted. Jack Sock's biggest leaks: forehand execution −3.1, backhand execution −2.9, slice shot selection −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.

ShotJack SockJuan Martin Del Potro
DirSelExecTotalDirSelExecTotal
Serve 1st −0.5 −0.1 ±0.0 −0.6 −0.1 ±0.0 +1.4 +1.2
Serve 2nd ±0.0 ±0.0 −0.4 −0.4 ±0.0 ±0.0 −0.3 −0.4
Return ±0.0 −0.4 +1.2 +0.8 +0.3 +0.1 +2.1 +2.5
Forehand −0.3 +2.4 −3.1 −1.0 +0.3 +1.2 +2.3 +3.8
Backhand ±0.0 ±0.0 −2.9 −2.9 +0.2 +0.1 +1.5 +1.7
Slice −0.1 −2.3 −0.1 −2.5 +0.5 −1.6 +1.2 +0.1
Net +0.4 +0.9 +1.5 +2.9 +0.2 ±0.0 +1.7 +1.9
Touch ±0.0 +0.5 +0.6 +1.1 +0.1 −0.2 −1.0 −1.1
Other ±0.0 −0.6 +0.2 −0.4 ±0.0 ±0.0 ±0.0 ±0.0
All shots −0.6+0.5 −2.9−3.0 +1.3−0.5 +8.9+9.7

Set by set

SetJack SockJuan Martin Del PotroNet, Jack
1−1.3+3.3 −4.6
2−1.7+6.4 −8.1

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.

Jack Sock serving

SetWideBodyT
1 33% 91% 30% 60% 36% 50%
2 27% 67% 23% 0% 50% 45%

Set to set −0.64 per 100 first serves in sets 2+

Within sets +0.54 per 100 first serves, every two to three service games

Juan Martin Del Potro serving

SetWideBodyT
1 28% 100% 21% 50% 52% 87%
2 50% 100% 7% 0% 43% 83%

Set to set +0.22 per 100 first serves in sets 2+

Within sets +0.14 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.

Jack Sock

5.1 points left on the table across 162 shots 3.17 per 100 shots

  1. Serve +1: drive to your backhand side hit BH slice through the middle ×3; BH slice down the line rates higher · 0.52 pts
  2. Serve +1: drive to your middle hit FH through the middle ×3; FH crosscourt rates higher · 0.37 pts
  3. Rally, shots 5–8: volley to your backhand side, opponent at net hit BH volley through the middle ×1; BH volley crosscourt rates higher · 0.24 pts
  4. Rally, shots 5–8: drive to your forehand side hit FH through the middle ×4; FH crosscourt rates higher · 0.20 pts

Juan Martin Del Potro

2.8 points left on the table across 167 shots 1.65 per 100 shots

  1. Serve +1: drive to your middle hit FH through the middle ×2; FH crosscourt rates higher · 0.25 pts
  2. Return +1: drive to your forehand side hit FH through the middle ×3; FH crosscourt rates higher · 0.18 pts
  3. Return +1: drive to your backhand side hit BH slice through the middle ×2; BH slice crosscourt rates higher · 0.17 pts
  4. Serve +1: slice to your middle hit FH through the middle ×1; FH crosscourt rates higher · 0.14 pts