US Open · SF · Hard · 6 Sep 1980

Johan Kriek v Bjorn Borg

100–132 in points · Bjorn Borg won

Why it went the way it did

Bjorn Borg won 22.6 more points than Johan Kriek relative to what the serve alone predicted. Johan Kriek's biggest leaks: serve 1st execution −4.3, net execution −4.2, forehand execution −3.4.

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.

Shot	Johan Kriek				Bjorn Borg
Shot	Dir	Sel	Exec	Total	Dir	Sel	Exec	Total
Serve 1st	+0.6	+0.7	−4.3	−3.1	+0.3	−0.5	−2.6	−2.7
Serve 2nd	+0.3	+0.8	−1.2	±0.0	±0.0	−0.6	+0.4	−0.3
Return	+0.3	−1.4	−0.6	−1.7	+0.8	+1.0	+5.7	+7.4
Forehand	+0.3	+0.7	−3.4	−2.4	−0.2	+0.9	+1.2	+1.8
Backhand	+0.3	+0.7	−3.0	−2.1	−0.1	+0.1	+2.1	+2.0
Slice	+0.3	−0.7	−2.4	−2.8	+0.4	−1.5	−0.6	−1.7
Net	±0.0	−0.5	−4.2	−4.7	+0.3	+0.4	−1.6	−0.9
Touch	−0.1	−0.5	+0.4	−0.2	+0.1	+0.2	−0.4	−0.2
All shots	+2.0	−0.3	−18.8	−17.0	+1.6	−0.1	+4.0	+5.5

Set by set

Set	Johan Kriek	Bjorn Borg	Net, Johan
2	+1.6	+0.5	+1.1
3	−7.1	+2.6	−9.7
4	−7.0	+0.5	−7.5
5	−4.6	+1.9	−6.5

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.

Johan Kriek serving

Set	Wide	Body	T
2	56% 80%	–	44% 25%
3	56% 46%	–	44% 42%
4	53% 25%	7% 0%	40% 17%
5	75% 44%	–	25% 33%

Set to set +4.05 per 100 first serves in sets 2+

Within sets +1.36 per 100 first serves, every two to three service games

Bjorn Borg serving

Set	Wide	Body	T
2	33% 50%	–	67% 25%
3	65% 69%	–	35% 71%
4	45% 70%	–	55% 67%
5	41% 43%	–	59% 90%

Set to set −0.62 per 100 first serves in sets 2+

Within sets −0.45 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.

Johan Kriek

6.7 points left on the table across 219 shots 3.06 per 100 shots

Rally, shots 5–8: drive to your forehand side, you at net hit FH volley through the middle ×3; FH volley crosscourt rates higher · 0.85 pts
Serve +1: mid-depth return to your backhand side, you at net hit BH volley through the middle ×3; BH volley crosscourt rates higher · 0.84 pts
Serve +1: short return to your forehand side, you at net hit FH volley through the middle ×2; FH volley crosscourt rates higher · 0.50 pts
Rally, shots 5–8: volley to your middle, opponent at net, you at net hit FH through the middle ×1; FH down the line rates higher · 0.30 pts

Bjorn Borg

6.7 points left on the table across 229 shots 2.91 per 100 shots

Rally, shots 5–8: drive to your backhand side, you at net hit BH volley through the middle ×1; BH volley crosscourt rates higher · 0.26 pts
Return of a 1st serve, wide, ad court, server rushing the net hit BH through the middle ×3; BH crosscourt rates higher · 0.23 pts
Return +1: volley to your forehand side, opponent at net hit FH through the middle ×1; FH crosscourt rates higher · 0.23 pts
Return of a 1st serve, wide, ad court, server rushing the net hit BH down the line ×5; BH crosscourt rates higher · 0.23 pts