RallyIQ

Game plan

Serena Williams v Caty Mcnally

Every number combines what Serena Williams does well with what Caty Mcnally allows, each measured against the tour average and shrunk toward it when the sample is thin. Flip perspective

Forecast

Serena Williams wins, best of 3 98%90%: 94%–100% · best of 5: 100%
Serve points won 65.9% / 49.9% Serena / Caty · tour 56.4%
Strengths only, no similarity priors 98%serve 66.0% / 49.8%

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 At least one of them is no longer active or has too little charted in the last three seasons, so both are compared on their careers.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 Serena Williams's record against Caty Mcnally's tactical lookalikes and in their charted head-to-heads (lookalikes: −0.7 on serve, −0.3 on return vs expectation (410 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

CareerSerenaCaty
Direction choice+0.34 ±0.04
better than 97%
−0.32 ±0.11
better than 5%
Shot selection+0.47 ±0.05
better than 93%
+0.05 ±0.33
better than 50%
Execution−0.04 ±0.27
better than 59%
−0.93 ±0.98
better than 20%
Points left on the table2.20 ±0.07
lower than 94%
3.33 ±0.16
lower than 2%

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.

Serena Williams serving

Deuce court

1st serveNowSerena winsv CatyMatchupOptimal
Wide50%70%66%70.6%±6.465% ▲
Body8%62%52%56.3%±10.30% ▼
T42%79%61%74.1%±6.235% ▼

Optimal v Caty Mcnally: +0.7±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 serveNowSerena winsv CatyMatchupOptimal
Wide45%75%67%76.3%±5.936% ▼
Body6%60%65%68.8%±10.40% ▼
T49%70%73%77.0%±5.964% ▲

Optimal v Caty Mcnally: +0.6±0.8 per 100 first serves (faults included) over the current mix, inside the 90% margin. Serving T every time would read +0.8 per 100 first serves in before the returner adjusts.

Caty Mcnally serving

Deuce court

1st serveNowCaty winsv SerenaMatchupOptimal
Wide43%63%65%61.6%±6.459% ▲
Body19%60%53%55.9%±8.93% ▼
T38%62%66%59.6%±7.638%

Optimal v Serena Williams: +1.1±1.0 per 100 first serves (faults included) over the current mix. Serving wide every time would read +1.8 per 100 first serves in before the returner adjusts.

Ad court

1st serveNowCaty winsv SerenaMatchupOptimal
Wide33%57%66%56.9%±8.547% ▲
Body20%51%57%52.4%±9.121% ▲
T48%58%61%54.9%±6.832% ▼

Optimal v Serena Williams: +0.4±0.9 per 100 first serves (faults included) over the current mix, inside the 90% margin. Serving wide every time would read +1.8 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.

Serena Williams returning

1st serve to the forehand

ReturnNowTourOwnv CatyValue
FH through the middle49%+4.2−2.6−0.5+1.0±2.2
FH crosscourt36%+5.3−1.6+1.3+5.0±3.4
FH down the line11%+1.5−0.4+0.5+1.6±4.2
BH through the middle1%+5.2−3.4+0.9+2.8±2.7
FH slice through the middle1%−6.7−0.7−0.8−8.2±2.3

Lean FH crosscourt: +2.5±2.5 per 100 returns v the current mix (2166 returns charted)

1st serve to the backhand

ReturnNowTourOwnv CatyValue
BH through the middle48%+6.0+0.3+0.9+7.2±2.1
BH crosscourt33%+7.7+1.3+3.1+12.2±2.9
BH down the line12%+2.2+1.1+2.9+6.2±4.2
BH slice through the middle3%−6.2−4.5−0.1−10.9±2.4
BH slice crosscourt2%−4.2−2.8+0.4−6.6±2.5

Lean BH crosscourt: +4.4±2.3 per 100 returns v the current mix (1939 returns charted)

2nd serve to the forehand

ReturnNowTourOwnv CatyValue
FH crosscourt43%+0.5−0.5−0.6−0.5±3.7
FH through the middle37%−3.2−0.1+0.9−2.4±2.7
FH down the line18%−0.6+5.3+1.1+5.8±5.0
BH inside-in1%+2.0−1.4−0.1+0.4±3.4
BH through the middle1%−1.0−0.2−1.4−2.6±2.2

Lean FH down the line: +5.9±4.5 per 100 returns v the current mix (750 returns charted)

2nd serve to the backhand

ReturnNowTourOwnv CatyValue
BH crosscourt51%+1.5+0.9−0.1+2.2±2.9
BH through the middle30%−2.6−1.8−1.4−5.8±2.4
BH down the line17%−0.5+3.4+1.9+4.8±4.8
FH inside-in1%+0.7+0.7−0.6+0.9±4.0
FH inside-out1%+1.4+0.2+1.1+2.6±3.7

Lean BH down the line: +4.6±4.3 per 100 returns v the current mix (954 returns charted)

Caty Mcnally returning

1st serve to the forehand

ReturnNowTourOwnv SerenaValue
FH slice through the middle27%−6.7+1.1+2.1−3.5±2.3
FH through the middle25%+4.2−1.9−1.3+0.9±2.4
FH crosscourt20%+5.3−3.8−4.0−2.4±3.5
FH down the line14%+1.5+1.0−1.4+1.1±3.8
FH slice crosscourt10%−6.6+1.1−2.4−7.9±2.6

Lean FH down the line: +3.3±3.4 per 100 returns v the current mix (180 returns charted, inside the 90% margin)

1st serve to the backhand

ReturnNowTourOwnv SerenaValue
BH through the middle52%+6.0−0.2−1.0+4.9±2.2
BH crosscourt21%+7.7−0.8−0.2+6.7±3.1
BH down the line11%+2.2+1.2−4.1−0.8±3.8
BH slice through the middle7%−6.2+0.5−0.2−6.0±2.0
BH slice down the line5%−12.5−1.8−1.2−15.4±3.1

Lean BH crosscourt: +4.2±2.7 per 100 returns v the current mix (177 returns charted)

2nd serve to the forehand

ReturnNowTourOwnv SerenaValue
FH through the middle54%−3.2−2.0−0.9−6.1±2.5
FH crosscourt22%+0.5+1.9−3.0−0.6±3.3
FH down the line13%−0.6−1.0+0.6−1.0±3.6
FH slice through the middle11%−15.2+0.1−0.4−15.5±1.9

Lean FH through the middle: −0.9±1.4 per 100 returns v the current mix (54 returns charted, inside the 90% margin)

2nd serve to the backhand

ReturnNowTourOwnv SerenaValue
BH through the middle47%−2.6+1.7−0.3−1.1±2.2
BH crosscourt32%+1.5+2.2−0.2+3.4±2.8
FH through the middle9%−2.7+1.0−0.9−2.5±1.7
FH inside-in6%+0.7−0.3−3.0−2.6±3.0
FH inside-out6%+1.4+0.4+0.6+2.4±2.8

Lean BH crosscourt: +3.1±2.2 per 100 returns v the current mix (87 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.

Serena Williams

Favour

ShotEdgeOwnTheirs
BH to their forehand · return+6.3±5.0+1.3+5.0
BH to their backhand · return+5.4±4.0+0.4+5.0
FH to their backhand · return +1+5.3±4.8+1.7+3.5
FH to their forehand · serve +1+4.2±4.5+1.9+2.3
FH to their backhand · return+3.7±4.5+3.1+0.6
BH to their forehand · serve +1+3.3±5.6−1.6+4.9

Avoid

ShotEdgeOwnTheirs
FH to their forehand · return +1−4.5±4.4−3.0−1.6
FH to their forehand · rally−4.3±3.2−2.1−2.2
FH to their backhand · serve +1−2.6±4.3+3.4−6.0
BH to their backhand · rally−1.9±3.1−1.7−0.2
FH to the middle · rally−1.5±2.5−0.9−0.5

Caty Mcnally

Favour

ShotEdgeOwnTheirs
FH to their forehand · serve +1+3.7±4.6+3.6+0.1
FH slice to the middle · return+2.9±3.2±0.0+2.9
FH to their backhand · rally+2.2±3.4+1.8+0.4
FH to their forehand · rally+1.7±3.2+0.9+0.7
BH to the middle · serve +1+1.4±2.9+2.3−0.9
BH to their backhand · rally+1.3±3.7+0.8+0.5

Avoid

ShotEdgeOwnTheirs
FH to their backhand · return +1−5.7±5.0−5.8+0.1
BH to their forehand · rally−4.8±5.3−4.6−0.2
FH to the middle · return−3.9±2.9−2.5−1.4
BH to the middle · return−3.1±2.4−0.8−2.3
FH to their backhand · serve +1−1.8±4.2+0.6−2.3

Against Caty Mcnally-like opponents

Serena Williams vMatchesServe pts wonReturn pts won
All charted opponents–62.1%45.1%
Players most similar to Caty Mcnally4 61.8%44.4%

Similar by tactical fingerprint: Karolina Muchova, Bianca Andreescu, Jessica Pegula, Jasmine Paolini, Emma Navarro, Shuai Zhang, Barbora Strycova, Alison Van Uytvanck, R, Andrea Petkovic. When two players have rarely met, their records against these lookalikes fill the gap.