RallyIQ

WTA · Right-handed · 36 charted matches · 2013–2026

Sloane Stephens

Archetype: Rarely serves the T · Patient builder

Against an average opponent

Serve points won 58.4% ±2.7 raw 56.4% · tour 56.3% · 2,396 points
Return points won 46.5% ±2.7 raw 42.7% · tour 43.7% · 2,349 points

Serve and return points won, refitted against every opponent at once so a record built on weak or strong opposition is put on the same scale. Career, all surfaces, with a 90% margin. Raw is the plain share of points won.

Value per 100 shots

Direction choice −0.12 ±0.11 better than 32% of WTA · raw −0.13
Shot selection −0.16 ±0.14 better than 31% of WTA · raw −0.17
Execution −0.13 ±0.58 better than 56% of WTA · raw −0.23
Tactical adaptability −0.13 first serves toward what's working, set to set · 36 matches
Adaptation speed +0.02 same, every two to three service games · per 100 first serves
Points left on the table 2.62 per 100 shots vs best direction · lower than 48% of WTA

Points gained per 100 shots compared with an average tour player in the same position, adjusted for the strength of the opponents faced, with a 90% margin (shots clustered by match). Raw is before the opponent adjustment. Built on 12,640 shots.

Shot expected value

The share of points Sloane Stephens goes on to win after each option in the positions they face most often, shrunk toward tour average when the sample is small. Showing the 8 most-used options; teal marks the best one with at least 30 shots.

Rally, shots 5–8: drive to your backhand side

position worth 45% to the average player · 1,025 shots

OptionUsedWin %Tour
BH through the middle 32% 43.8%±4.3 43.3%
BH crosscourt 31% 48.1%±4.5 47.6%
BH down the line 16% 51.8%±6.1 46.8%
BH slice crosscourt 8% 32.8%±7.6 40.4%
BH slice through the middle 6% 26.9%±7.9 34.4%
FH inside-out 3% 53.0%±11.6 52.5%
BH slice down the line 1% 33.4%±13.9 31.7%

Rally, shots 5–8: drive to your middle

position worth 50% to the average player · 767 shots

OptionUsedWin %Tour
FH crosscourt 24% 48.1%±5.7 52.7%
FH through the middle 22% 48.5%±6.0 45.8%
FH down the line 20% 55.6%±6.1 52.2%
BH through the middle 13% 50.6%±7.4 46.2%
BH crosscourt 9% 45.8%±8.6 50.9%
BH down the line 8% 51.2%±9.1 50.0%

Rally, shots 5–8: drive to your forehand side

position worth 43% to the average player · 663 shots

OptionUsedWin %Tour
FH crosscourt 42% 51.5%±4.8 46.7%
FH through the middle 29% 41.0%±5.5 41.3%
FH down the line 16% 41.8%±7.3 44.9%
FH slice through the middle 7% 33.1%±9.5 29.2%
FH slice crosscourt 5% 38.8%±11.3 31.9%

Return +1: drive to your backhand side

position worth 44% to the average player · 470 shots

OptionUsedWin %Tour
BH through the middle 32% 42.5%±6.2 43.0%
BH crosscourt 30% 52.5%±6.5 47.8%
BH down the line 18% 51.7%±8.0 46.2%
BH slice through the middle 9% 26.0%±9.0 33.2%
BH slice crosscourt 6% 31.8%±10.8 39.6%

Serve under pressure

Pressure predictability index +3 How much less varied Sloane Stephens's first-serve direction gets on break points. Positive means easier to read. Based on 280 break-point first serves.

Deuce court

1st serveUsageBreak ptWon when in
Wide 50% 46% 66% / 66%
Body 30% 29% 56% / 57%
T 20% 26% 63% / 68%

1,174 normal · 70 break-point 1st serves

Ad court

1st serveUsageBreak ptWon when in
Wide 33% 28% 60% / 66%
Body 14% 12% 53% / 56%
T 54% 60% 61% / 64%

933 normal · 210 break-point 1st serves

Is the serve mix in equilibrium?

Game theory says a well-mixed server wins equally often with every direction they use. If one direction wins more, it's underused and points are being left behind. This is the minimax test Walker and Wooders ran on Wimbledon finals, applied to every charted first serve. Win rates include faults. "Optimal" allows for returners reading a habit. A direction loses 0.19 points per 100 serves for every 10 points of habitual usage, measured from WTA servers whose mix drifted between matches. Shifts stay within the range servers' habits actually vary, the only range that response was measured over.

Deuce court

1st serveUsagePoints wonOptimal
Wide50% 59.0%±3.2 n=621 65% ▲
Body30% 56.2%±4.1 n=370 15% ▼
T20% 58.0%±4.8 n=253 20%

Consistent with an optimal mix (p = 0.63).
Optimal mix: +0.7 per 100 first serves.

Ad court

1st serveUsagePoints wonOptimal
Wide32% 55.4%±4.1 n=366 39% ▲
Body13% 49.5%±6.1 n=151 0% ▼
T55% 55.5%±3.2 n=626 61% ▲

Consistent with an optimal mix (p = 0.23).
Optimal mix: +0.7 per 100 first serves.

Exploitability 0.70 points per 100 first serves What the optimal mix would win over the current one, both courts. More exploitable than 100% of WTA servers. Tested on matches they weren't fitted on, WTA mixes picked this way win 0.42 per 100 first serves on average.

Repeating the previous direction to the same court: −1.3±3.4 points per 100 against switching. Negative means returners read repeats. Tour-wide, repeating costs women about 0.4 points per 100 and costs men nothing, so men's returners don't measurably anticipate direction. (870 repeats, 1,445 switches.)

Return by serve direction

Return points won against each serve direction, compared with the tour average.

ServeCourtDirectionPointsWonvs tour
1stAd courtBody 129 41% −2.9±6.4
1stAd courtT 250 33% −2.8±4.6
1stAd courtWide 315 36% +1.9±4.3
1stDeuce courtBody 209 42% −0.4±5.3
1stDeuce courtT 271 29% −2.7±4.3
1stDeuce courtWide 282 34% ±0.0±4.4
2ndAd courtBody 168 60% +4.8±5.7
2ndAd courtT 51 54% −1.3±9.1
2ndAd courtWide 204 51% −2.2±5.4
2ndDeuce courtBody 240 57% +2.7±5.0
2ndDeuce courtT 150 54% −1.7±6.1
2ndDeuce courtWide 74 53% −0.8±8.1

Signature patterns

Recurring sequences that win more than Sloane Stephens's own baseline, ranked by edge weighted by how often they're used.

Serve → +1

  1. Wide serve (ad court) → FH crosscourt used 2.8% · won 60% · +1.2±8.5 vs own baseline
  2. Wide serve (ad court) → BH crosscourt used 2.0% · won 57% · −2.0±9.5 vs own baseline
  3. Wide serve (deuce court) → FH down the line used 4.2% · won 58% · −1.4±7.3 vs own baseline
  4. T serve (ad court) → FH down the line used 2.9% · won 57% · −1.8±8.4 vs own baseline
  5. T serve (ad court) → FH crosscourt used 2.4% · won 55% · −3.9±9.0 vs own baseline

Return

  1. vs body serve (deuce court) → FH through the middle, deep used 2.6% · won 59% · +15.5±9.3 vs own baseline
  2. vs wide serve (ad court) → BH crosscourt, mid used 6.2% · won 52% · +9.0±6.9 vs own baseline
  3. vs wide serve (deuce court) → FH through the middle, mid used 3.0% · won 54% · +11.1±9.0 vs own baseline
  4. vs T serve (deuce court) → BH through the middle, deep used 2.9% · won 54% · +10.5±9.1 vs own baseline
  5. vs body serve (ad court) → BH through the middle, mid used 2.2% · won 52% · +9.0±10.0 vs own baseline

Rally, consecutive own shots

  1. BH crosscourt → FH crosscourt used 3.1% · won 59% · +10.2±7.9 vs own baseline
  2. FH crosscourt → FH crosscourt used 4.1% · won 57% · +7.5±7.0 vs own baseline
  3. BH through the middle → BH crosscourt used 3.4% · won 56% · +6.4±7.7 vs own baseline
  4. FH crosscourt → FH down the line used 4.2% · won 53% · +3.6±7.0 vs own baseline
  5. BH down the line → FH crosscourt used 2.7% · won 53% · +3.7±8.3 vs own baseline

Discovered sequences

Mined from every me → opponent → me run of three shots, with no templates. Ranked by how much more often Sloane Stephens wins the point once the sequence happens, weighted by how often it happens. Think of them as chess openings.

  1. FH through the middle → BH crosscourt → BH crosscourt used 0.6% · won 60% · +11.4±10.2 vs own baseline · +21.0 vs tour on the same sequence
  2. FH crosscourt → FH crosscourt → FH crosscourt used 1.4% · won 54% · +5.4±7.5 vs own baseline · +7.0 vs tour on the same sequence Disrupted by Caroline Wozniacki (3/7), Serena Williams (4/7)
  3. FH crosscourt → FH through the middle → FH down the line used 0.7% · won 54% · +5.7±9.5 vs own baseline · +3.5 vs tour on the same sequence
  4. FH crosscourt → FH down the line → BH crosscourt used 1.0% · won 53% · +4.8±8.4 vs own baseline · +5.3 vs tour on the same sequence Disrupted by Serena Williams (3/6), Victoria Azarenka (5/9)
  5. FH down the line → BH through the middle → FH crosscourt used 0.6% · won 55% · +6.1±9.9 vs own baseline · +1.1 vs tour on the same sequence
  6. BH down the line → FH through the middle → FH down the line used 0.4% · won 56% · +7.7±11.5 vs own baseline · +10.1 vs tour on the same sequence

Strengths and vulnerabilities

Value per 100 shots compared with the average player hitting (strengths) or facing (vulnerabilities) the same shot. Only shot types seen at least 120 times.

Hurts opponents most with

Wide 2nd serve · ad court+3.8189
BH to their forehand · return +1+2.3130
FH to their forehand · rally+1.3795
FH to their backhand · serve +1+1.2305
Body 2nd serve · deuce court+1.2202

Most exposed to

FH to the middle · return−2.1542
FH to their forehand · return−1.8263
FH to the middle · serve +1−1.3215
BH to their backhand · return−1.0393
FH to their backhand · return−0.5230

Best-equipped opponents

Active players whose shot mix lines up best against these weaknesses, by structural compatibility per 100 rally shots: Sara Sorribes Tormo +1.90, Caroline Wozniacki +1.49, Tatjana Maria +1.20, Daria Kasatkina +0.90, Sara Errani +0.84

Favourable matchups

Sara Errani +1.60, Marie Bouzkova +1.35, Angelique Kerber +1.30, Elina Avanesyan +1.06, Katie Volynets +0.90

Active players who are best at the shot in the top weakness: Elina Avanesyan, Caroline Wozniacki, Sara Sorribes Tormo, Lin Zhu, Qiang Wang

Tactical fingerprint

Each bar shows how far a style trait is from the WTA average, in standard deviations.

1st serve in70%
T serves · ad55%
Through the middle36%
Wide serves · deuce50%
Avg rally length4.3
BH down the line22%
Chipped returns13%
Unforced errors / shot11.0%
Run-around forehands8%
Backhand slice14%
Serve & volley0%
Point-ending shots23.2%
Deep returns30%
Points at net5%
FH down the line26%
Drop shots / shot0.8%
Forehand share50%
Wide serves · ad32%
T serves · deuce20%

Plays most like

  1. Lin Zhu 2016–2025 plan v
  2. Emma Raducanu 2018–2026 plan v
  3. Marie Bouzkova 2018–2026 plan v
  4. Carla Suarez Navarro 2009–2021 plan v
  5. Paula Badosa 2015–2026 plan v
  6. Marion Bartoli 2003–2013 plan v
  7. Kimberly Birrell 2016–2026 plan v
  8. Iva Jovic 2024–2026 plan v

Closest from another era

  1. Jennifer Capriati 1990–2002
  2. Elena Dementieva 1999–2010
  3. Anastasia Myskina 2002–2006

Charted matches