Game plan

Sloane Stephens v Ashleigh Barty

Every number combines what Sloane Stephens does well with what Ashleigh Barty 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 8%90%: 3%–19% · best of 5: 4%

Serve points won 53.9% / 64.5% Sloane / Ashleigh · tour 56.4%

Strengths only, no similarity priors 8%serve 53.7% / 64.8%

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 At least one of them is no longer active or has too little charted in the last three seasons, so both are compared on their careers.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 Ashleigh Barty's tactical lookalikes and in their charted head-to-heads (lookalikes: +2.5 on serve, +4.4 on return vs expectation (238 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

Career	Sloane	Ashleigh
Direction choice	−0.12 ±0.11 better than 32%	+0.27 ±0.07 better than 93%
Shot selection	−0.16 ±0.14 better than 31%	−1.27 ±0.17 better than 2%
Execution	−0.13 ±0.58 better than 56%	+0.79 ±0.31 better than 87%
Points left on the table	2.62 ±0.13 lower than 48%	2.65 ±0.10 lower than 42%

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.

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 serve	Now	Sloane wins	v Ashleigh	Matchup	Optimal
Wide	50%	66%	67%	66.6%±5.0	65% ▲
Body	30%	56%	57%	55.1%±7.0	15% ▼
T	20%	63%	62%	56.4%±6.9	20%

Optimal v Ashleigh Barty: +0.8±0.9 per 100 first serves (faults included) over the current mix, inside the 90% margin. Serving wide every time would read +5.5 per 100 first serves in before the returner adjusts.

Ad court

1st serve	Now	Sloane wins	v Ashleigh	Matchup	Optimal
Wide	32%	60%	64%	57.5%±6.0	47% ▲
Body	13%	53%	50%	46.3%±8.9	0% ▼
T	55%	61%	59%	56.1%±5.6	53% ▼

Optimal v Ashleigh Barty: +0.8±0.9 per 100 first serves (faults included) over the current mix, inside the 90% margin. Serving wide every time would read +2.2 per 100 first serves in before the returner adjusts.

Ashleigh Barty serving

Deuce court

1st serve	Now	Ashleigh wins	v Sloane	Matchup	Optimal
Wide	41%	73%	66%	72.5%±5.1	34% ▼
Body	8%	64%	58%	64.3%±8.4	0% ▼
T	51%	78%	71%	79.9%±4.3	66% ▲

Optimal v Sloane Stephens: +0.8±0.7 per 100 first serves (faults included) over the current mix. Serving T every time would read +4.3 per 100 first serves in before the returner adjusts.

Ad court

1st serve	Now	Ashleigh wins	v Sloane	Matchup	Optimal
Wide	44%	73%	64%	71.7%±5.4	38% ▼
Body	9%	62%	59%	64.5%±9.2	0% ▼
T	47%	73%	67%	74.9%±5.0	62% ▲

Optimal v Sloane Stephens: +0.9±0.8 per 100 first serves (faults included) over the current mix. Serving T every time would read +2.4 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

Return	Now	Tour	Own	v Ashleigh	Value
FH through the middle	37%	+4.2	+2.0	−0.3	+5.9±2.4
FH slice through the middle	20%	−6.7	−0.4	−1.6	−8.7±2.4
FH crosscourt	14%	+5.3	−1.5	−1.6	+2.2±4.1
FH down the line	13%	+1.5	−0.6	−2.9	−1.9±4.3
FH slice crosscourt	12%	−6.6	+0.3	−0.4	−6.8±2.8

Lean FH through the middle: +6.9±1.8 per 100 returns v the current mix (466 returns charted)

1st serve to the backhand

Return	Now	Tour	Own	v Ashleigh	Value
BH through the middle	43%	+6.0	−0.1	+1.8	+7.7±2.2
BH crosscourt	32%	+7.7	+0.3	+0.2	+8.2±3.2
BH down the line	10%	+2.2	−3.1	−2.8	−3.7±4.6
BH slice through the middle	8%	−6.2	−2.7	−0.4	−9.3±2.5
BH slice crosscourt	4%	−4.2	−1.3	+0.5	−5.0±2.9

Lean BH crosscourt: +4.2±2.4 per 100 returns v the current mix (509 returns charted)

2nd serve to the forehand

Return	Now	Tour	Own	v Ashleigh	Value
FH through the middle	58%	−3.2	+0.2	−0.1	−3.1±2.9
FH crosscourt	26%	+0.5	−1.5	−1.3	−2.3±4.2
FH down the line	10%	−0.6	−0.5	−1.7	−2.8±4.4
FH slice through the middle	6%	−15.2	−0.8	+0.4	−15.7±2.0

Lean FH crosscourt: +1.3±3.6 per 100 returns v the current mix (88 returns charted, inside the 90% margin)

2nd serve to the backhand

Return	Now	Tour	Own	v Ashleigh	Value
BH through the middle	45%	−2.6	−0.9	+1.2	−2.3±2.1
BH crosscourt	41%	+1.5	−1.0	−1.9	−1.4±2.9
BH down the line	6%	−0.5	−0.1	+2.3	+1.7±4.7
FH through the middle	5%	−2.7	±0.0	−0.1	−2.8±2.3
FH inside-out	3%	+1.4	+2.3	−1.7	+1.9±3.6

Lean BH down the line: +3.3±4.7 per 100 returns v the current mix (299 returns charted, inside the 90% margin)

Ashleigh Barty returning

1st serve to the forehand

Return	Now	Tour	Own	v Sloane	Value
FH through the middle	43%	+4.2	±0.0	+1.2	+5.3±2.0
FH crosscourt	25%	+5.3	−1.0	+0.8	+5.1±3.6
FH down the line	17%	+1.5	+3.2	+0.6	+5.3±4.1
FH slice through the middle	9%	−6.7	−0.6	−1.7	−9.0±2.5
FH slice crosscourt	4%	−6.6	−1.0	−1.3	−8.9±2.7

Lean FH down the line: +2.3±3.6 per 100 returns v the current mix (769 returns charted, inside the 90% margin)

1st serve to the backhand

Return	Now	Tour	Own	v Sloane	Value
BH slice through the middle	29%	−6.2	+1.7	−0.4	−4.9±2.2
BH through the middle	29%	+6.0	−0.9	−0.4	+4.7±2.1
BH crosscourt	17%	+7.7	−0.3	+2.2	+9.6±3.1
BH slice crosscourt	12%	−4.2	+0.7	±0.0	−3.4±2.6
BH down the line	7%	+2.2	−0.2	−1.0	+1.0±4.5

Lean BH crosscourt: +8.9±2.7 per 100 returns v the current mix (911 returns charted)

2nd serve to the forehand

Return	Now	Tour	Own	v Sloane	Value
FH crosscourt	47%	+0.5	+2.4	+1.6	+4.5±4.4
FH through the middle	40%	−3.2	−1.6	−0.2	−5.0±3.1
FH down the line	13%	−0.6	+2.4	−0.9	+1.0±5.0

Lean FH crosscourt: +4.2±2.7 per 100 returns v the current mix (161 returns charted)

2nd serve to the backhand

Return	Now	Tour	Own	v Sloane	Value
BH slice crosscourt	24%	−7.5	−1.7	±0.0	−9.2±1.9
BH through the middle	23%	−2.6	−3.0	−2.3	−7.9±2.5
BH crosscourt	16%	+1.5	+1.4	−0.5	+2.5±3.3
BH slice through the middle	14%	−11.7	−0.3	±0.0	−12.0±1.7
BH down the line	7%	−0.5	−1.2	−0.4	−2.1±5.2

Lean BH crosscourt: +8.3±2.9 per 100 returns v the current mix (526 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 hard. Each player's hard record is shrunk toward their all-surface one, so a thin sample on it moves the numbers only a little.

Sloane Stephens

Favour

Shot	Edge	Own	Theirs
BH to their forehand · return	+0.2±5.6	±0.0	+0.3
BH to their backhand · serve +1	−0.1±3.4	+1.7	−1.8
BH to the middle · serve +1	−0.1±2.6	−0.8	+0.7
FH to the middle · return	−0.2±2.4	+0.2	−0.3
BH to their forehand · serve +1	−0.5±5.5	+1.2	−1.7
FH to their forehand · rally	−0.6±2.4	+0.9	−1.5

Avoid

Shot	Edge	Own	Theirs
FH to their forehand · return	−9.5±5.0	−5.7	−3.9
FH to their forehand · return +1	−8.0±4.1	−4.9	−3.1
BH slice to the middle · rally	−7.3±2.8	−2.9	−4.4
FH to their forehand · serve +1	−5.9±3.9	−1.5	−4.3
FH to their backhand · return +1	−5.3±5.0	−2.9	−2.4

Ashleigh Barty

Favour

Shot	Edge	Own	Theirs
BH to their backhand · return	+5.0±3.5	+2.3	+2.7
FH to their forehand · return	+3.9±4.4	+0.4	+3.5
FH to their backhand · return	+3.8±4.7	+4.5	−0.7
FH to the middle · serve +1	+2.7±2.8	+0.8	+1.8
FH to the middle · return	+1.9±2.2	−0.6	+2.6
FH to their forehand · serve +1	+1.2±3.7	+1.7	−0.5

Avoid

Shot	Edge	Own	Theirs
FH to their backhand · rally	−5.0±2.8	−0.1	−5.0
BH to their forehand · return +1	−4.2±6.8	−1.7	−2.5
FH to their forehand · rally	−3.2±2.3	+0.2	−3.4
BH to the middle · serve +1	−2.8±2.7	−2.8	±0.0
BH to their backhand · rally	−2.8±2.8	−1.8	−1.0

Against Ashleigh Barty-like opponents

Sloane Stephens v	Matches	Serve pts won	Return pts won
All charted opponents	–	56.4%	42.8%
Players most similar to Ashleigh Barty	2	58.5%	47.5%

Similar by tactical fingerprint: Karolina Muchova, Barbora Krejcikova, Clara Tauson, Diane Parry, Maria Sakkari, Jennifer Brady, Polona Hercog, Kiki Bertens, Francesca Schiavone, Roberta Vinci. When two players have rarely met, their records against these lookalikes fill the gap.