RallyIQ

Game plan

Sloane Stephens v Coco Gauff

Every number combines what Sloane Stephens does well with what Coco Gauff allows, each measured against the tour average and shrunk toward it when the sample is thin. Flip perspective

Forecast

Sloane Stephens wins, best of 3 49%90%: 19%–79% · best of 5: 48%
Serve points won 59.9% / 60.2% Sloane / Coco · tour 58.1%
Strengths only, no similarity priors 45%serve 58.6% / 59.6%

Each player's serve and return strength is fitted against every opponent they were charted against, so a record built on weak opponents counts for less. At least one of them is no longer active or has too little charted in the last three seasons, so both are compared on their careers. The result is then nudged by Sloane Stephens's record against Coco Gauff's tactical lookalikes and in their charted head-to-heads (lookalikes: +10.5 on serve, −12.0 on return vs expectation (147 points); head-to-head: +24.9 on serve, −1.0 on return vs expectation (99 points)). A game-by-game Markov chain turns point odds into match odds; the 90% range covers the uncertainty in the two strengths, not the nudges. Charted matches lean toward big events, so treat this as a scouting estimate, not a betting line.

Head to head, per 100 shots

CareerSloaneCoco
Direction choice−0.12 ±0.11
better than 32%
−0.25 ±0.04
better than 11%
Shot selection−0.16 ±0.14
better than 31%
+0.40 ±0.08
better than 89%
Execution−0.13 ±0.58
better than 56%
+0.41 ±0.27
better than 76%
Points left on the table2.62 ±0.13
lower than 48%
2.86 ±0.06
lower than 20%

Each player's career against an average tour player in the same position, adjusted for opponent strength, with a 90% margin (shots clustered by match). Points left on the table is the gap to the best-value direction for the same stroke, so lower is better. Percentiles are within each player's own tour. A side is highlighted only when the gap is larger than the margin on the difference.

Structural compatibility

Expected edge per 100 rally shots from style alone: Sloane Stephens −1.01, Coco Gauff −0.17. Each player's shot mix weighted by their own skill with each shot and by how much the other gives up against it. This is why some rankings gaps don't hold in a given matchup.

Serve plan

The share of points the server wins when a first serve lands in that direction (hover a rate for its 90% interval; ± is the 90% margin). "Matchup" combines the server's rate with how this returner handles that serve. "Optimal" is the mix that wins most against this returner once they start reading a habit, at the response measured across the tour, and only within the range servers' habits actually vary. The gain over the current mix is how exploitable that mix is.

Sloane Stephens serving

Deuce court

1st serveNowSloane winsv CocoMatchupOptimal
Wide50%66%62%61.7%±4.450%
Body30%56%58%56.0%±5.715% ▼
T20%63%69%63.6%±6.435% ▲

Optimal v Coco Gauff: +0.5±0.8 per 100 first serves (faults included) over the current mix, inside the 90% margin. Serving T every time would read +3.2 per 100 first serves in before the returner adjusts.

Ad court

1st serveNowSloane winsv CocoMatchupOptimal
Wide32%60%60%53.5%±5.730% ▼
Body13%53%56%52.9%±7.80% ▼
T55%61%60%56.4%±4.770% ▲

Optimal v Coco Gauff: +0.5±0.8 per 100 first serves (faults included) over the current mix, inside the 90% margin. Serving T every time would read +1.4 per 100 first serves in before the returner adjusts.

Coco Gauff serving

Deuce court

1st serveNowCoco winsv SloaneMatchupOptimal
Wide47%72%66%71.7%±4.562% ▲
Body25%62%58%62.1%±5.910% ▼
T28%74%71%76.3%±4.728%

Optimal v Sloane Stephens: +1.0±0.8 per 100 first serves (faults included) over the current mix. Serving T every time would read +5.8 per 100 first serves in before the returner adjusts.

Ad court

1st serveNowCoco winsv SloaneMatchupOptimal
Wide37%69%64%67.6%±4.924% ▼
Body24%63%59%66.2%±6.723% ▼
T38%71%67%73.9%±4.753% ▲

Optimal v Sloane Stephens: +0.2±0.7 per 100 first serves (faults included) over the current mix, inside the 90% margin. Serving T every time would read +4.2 per 100 first serves in before the returner adjusts.

Return plan

Value of each return, in points per 100 returns against an average return of the same serve (direction, court, surface): the tour's result with that return, the returner's own edge with it, and what this server gives up when it comes back to that side. Returns with no charted direction are left out, so values compare with each other rather than with zero. Depth isn't a choice here: missed returns have no depth. Serve quality isn't charted, so a block through the middle partly reflects the serve that forced it.

Sloane Stephens returning

1st serve to the forehand

ReturnNowTourOwnv CocoValue
FH through the middle37%+4.2+2.0−1.4+4.8±2.2
FH slice through the middle20%−6.7−0.4−1.1−8.2±2.2
FH crosscourt14%+5.3−1.5−1.4+2.4±3.6
FH down the line13%+1.5−0.6−2.2−1.3±4.1
FH slice crosscourt12%−6.6+0.3−1.1−7.5±2.7

Lean FH through the middle: +5.9±1.6 per 100 returns v the current mix (466 returns charted)

1st serve to the backhand

ReturnNowTourOwnv CocoValue
BH through the middle43%+6.0−0.1−1.5+4.4±1.9
BH crosscourt32%+7.7+0.3+1.7+9.7±2.7
BH down the line10%+2.2−3.1−5.3−6.2±4.0
BH slice through the middle8%−6.2−2.7−2.7−11.6±2.4
BH slice crosscourt4%−4.2−1.3−0.6−6.0±2.9

Lean BH crosscourt: +7.0±2.1 per 100 returns v the current mix (509 returns charted)

2nd serve to the forehand

ReturnNowTourOwnv CocoValue
FH through the middle58%−3.2+0.2−1.6−4.6±2.5
FH crosscourt26%+0.5−1.5−3.4−4.4±3.5
FH down the line10%−0.6−0.5−1.8−2.9±4.3
FH slice through the middle6%−15.2−0.8−1.0−17.0±2.0

Lean FH crosscourt: +0.7±3.0 per 100 returns v the current mix (88 returns charted, inside the 90% margin)

2nd serve to the backhand

ReturnNowTourOwnv CocoValue
BH through the middle45%−2.6−0.9−0.6−4.2±2.1
BH crosscourt41%+1.5−1.0−1.1−0.6±3.0
BH down the line6%−0.5−0.1−5.0−5.7±4.3
FH through the middle5%−2.7±0.0−1.6−4.3±1.9
FH inside-out3%+1.4+2.3−1.8+1.9±3.5

Lean BH crosscourt: +2.0±2.0 per 100 returns v the current mix (299 returns charted, inside the 90% margin)

Coco Gauff returning

1st serve to the forehand

ReturnNowTourOwnv SloaneValue
FH through the middle57%+4.2+1.0+1.2+6.3±1.6
FH down the line20%+1.5+0.3+0.6+2.4±3.5
FH crosscourt19%+5.3−2.0+0.8+4.0±3.2
FH slice through the middle2%−6.7+0.3−1.7−8.1±2.6
FH slice crosscourt1%−6.6−1.7−1.3−9.6±2.6

Lean FH through the middle: +1.8±1.1 per 100 returns v the current mix (2148 returns charted)

1st serve to the backhand

ReturnNowTourOwnv SloaneValue
BH through the middle52%+6.0+1.5−0.4+7.1±1.8
BH crosscourt27%+7.7+1.5+2.2+11.4±2.7
BH down the line12%+2.2−0.8−1.0+0.4±4.2
BH slice through the middle5%−6.2−3.4−0.4−10.0±2.5
BH slice crosscourt2%−4.2−2.2±0.0−6.4±2.6

Lean BH crosscourt: +5.5±2.3 per 100 returns v the current mix (1176 returns charted)

2nd serve to the forehand

ReturnNowTourOwnv SloaneValue
FH through the middle55%−3.2+0.5−0.2−2.9±2.6
FH crosscourt27%+0.5+1.8+1.6+4.0±4.1
FH down the line15%−0.6−5.0−0.9−6.4±5.1
BH through the middle1%−1.0+0.8−2.3−2.4±1.9
BH inside-out1%+2.2−0.5−0.4+1.3±3.7

Lean FH crosscourt: +5.4±3.4 per 100 returns v the current mix (670 returns charted)

2nd serve to the backhand

ReturnNowTourOwnv SloaneValue
BH crosscourt46%+1.5+0.6−0.5+1.6±2.8
BH through the middle44%−2.6+2.1−2.3−2.8±2.2
BH down the line9%−0.5−0.1−0.4−1.0±5.2

Lean BH crosscourt: +2.2±1.8 per 100 returns v the current mix (711 returns charted)

Rally plan

Edge, in points per 100 shots: the hitter's skill with the shot (own) plus how much the receiver usually gives up against it (theirs), both measured against the tour average on grass. Each player's grass record is shrunk toward their all-surface one, so a thin sample on it moves the numbers only a little.

Sloane Stephens

Favour

ShotEdgeOwnTheirs
BH to their backhand · return +1+5.3±4.6+3.3+1.9
BH to their forehand · serve +1+3.6±5.9+3.8−0.2
FH to their forehand · rally+3.2±3.9+2.8+0.4
BH to their backhand · return+2.3±4.5−1.0+3.3
BH to the middle · rally+2.1±2.9+1.5+0.6
BH to their backhand · serve +1+2.1±4.6−0.1+2.2

Avoid

ShotEdgeOwnTheirs
FH to their forehand · return−11.0±5.5−5.0−6.0
BH to their forehand · return−10.8±5.8−5.6−5.2
BH to their forehand · rally−7.5±5.6−1.1−6.3
BH slice to the middle · rally−3.4±3.0−3.7+0.3
FH slice to the middle · rally−3.4±3.5−3.1−0.3

Coco Gauff

Favour

ShotEdgeOwnTheirs
BH to their forehand · serve +1+5.3±5.9+4.3+1.1
BH to their backhand · return+3.6±4.5+0.9+2.7
FH to their backhand · return+2.7±5.6+0.1+2.6
FH to the middle · return+2.5±3.3+0.7+1.8
FH to the middle · serve +1+2.3±3.5+2.2+0.1
FH to their forehand · return +1+1.4±5.1+0.3+1.1

Avoid

ShotEdgeOwnTheirs
FH to their backhand · serve +1−6.7±5.3−1.5−5.2
FH to their forehand · rally−4.6±4.1−1.5−3.1
BH to their forehand · rally−4.2±5.7−0.5−3.7
FH to their backhand · return +1−3.1±5.5−3.3+0.2
FH to their backhand · rally−3.0±4.7−2.6−0.4

Against Coco Gauff-like opponents

Sloane Stephens vMatchesServe pts wonReturn pts won
All charted opponents–56.4%42.8%
Players most similar to Coco Gauff1 67.5%30.0%
Coco Gauff (charted head-to-head)1 79.6%40.0%

Similar by tactical fingerprint: Iva Jovic, Cristina Bucsa, Marie Bouzkova, Belinda Bencic, Elise Mertens, Emma Navarro, Emma Raducanu, Yafan Wang, Nao Hibino, Shelby Rogers. When two players have rarely met, their records against these lookalikes fill the gap.

Charted head-to-head