Game plan

Bianca Andreescu v Serena Williams

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

Forecast

Bianca Andreescu wins, best of 3 14%90%: 5%–32% · best of 5: 9%

Serve points won 54.5% / 62.8% Bianca / Serena · tour 56.3%

Strengths only, no similarity priors 17%serve 55.6% / 63.1%

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 At least one of them is no longer active or has too little charted in the last three seasons, so both are compared on their careers.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 Bianca Andreescu's record against Serena Williams's tactical lookalikes and in their charted head-to-heads (lookalikes: −3.9 on serve, −1.5 on return vs expectation (1407 points); head-to-head: +1.9 on serve, +13.6 on return vs expectation (173 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	Bianca	Serena
Direction choice	−0.35 ±0.03 better than 4%	+0.34 ±0.04 better than 97%
Shot selection	−0.08 ±0.07 better than 36%	+0.47 ±0.05 better than 93%
Execution	−0.56 ±0.16 better than 31%	−0.04 ±0.27 better than 59%
Points left on the table	3.03 ±0.04 lower than 10%	2.20 ±0.07 lower than 94%

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: Bianca Andreescu −0.56, Serena Williams −1.70. 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.

Bianca Andreescu serving

Deuce court

1st serve	Now	Bianca wins	v Serena	Matchup	Optimal
Wide	38%	67%	65%	65.7%±2.8	53% ▲
Body	30%	59%	53%	54.8%±3.5	14% ▼
T	32%	72%	66%	70.0%±2.9	33%

Optimal v Serena Williams: +1.2±0.5 per 100 first serves (faults included) over the current mix. Serving T every time would read +6.2 per 100 first serves in before the returner adjusts.

Ad court

1st serve	Now	Bianca wins	v Serena	Matchup	Optimal
Wide	39%	67%	66%	67.0%±3.0	54% ▲
Body	27%	57%	57%	58.4%±3.8	27%
T	34%	65%	61%	61.6%±3.1	19% ▼

Optimal v Serena Williams: +0.3±0.5 per 100 first serves (faults included) over the current mix, inside the 90% margin. Serving wide every time would read +4.2 per 100 first serves in before the returner adjusts.

Serena Williams serving

Deuce court

1st serve	Now	Serena wins	v Bianca	Matchup	Optimal
Wide	50%	70%	68%	71.7%±2.5	65% ▲
Body	8%	62%	56%	61.1%±5.0	0% ▼
T	42%	79%	66%	77.8%±2.5	35% ▼

Optimal v Bianca Andreescu: +0.7±0.5 per 100 first serves (faults included) over the current mix. Serving T every time would read +4.4 per 100 first serves in before the returner adjusts.

Ad court

1st serve	Now	Serena wins	v Bianca	Matchup	Optimal
Wide	45%	75%	68%	77.1%±2.5	60% ▲
Body	6%	60%	57%	61.2%±5.7	0% ▼
T	49%	70%	64%	69.7%±2.7	40% ▼

Optimal v Bianca Andreescu: +0.4±0.4 per 100 first serves (faults included) over the current mix, inside the 90% margin. Serving wide every time would read +4.6 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.

Bianca Andreescu returning

1st serve to the forehand

Return	Now	Tour	Own	v Serena	Value
FH through the middle	51%	+4.2	+0.7	−1.3	+3.6±1.2
FH down the line	16%	+1.5	−3.9	−1.4	−3.9±2.9
FH slice through the middle	13%	−6.7	−1.5	+2.1	−6.1±1.8
FH crosscourt	13%	+5.3	−2.7	−4.0	−1.4±2.7
FH slice crosscourt	4%	−6.6	−3.1	−2.4	−12.1±2.7

Lean FH through the middle: +4.1±0.9 per 100 returns v the current mix (2739 returns charted)

1st serve to the backhand

Return	Now	Tour	Own	v Serena	Value
BH through the middle	55%	+6.0	−0.2	−1.0	+4.9±1.2
BH crosscourt	17%	+7.7	−1.3	−0.2	+6.2±2.3
BH down the line	16%	+2.2	+0.1	−4.1	−1.8±3.1
BH slice through the middle	7%	−6.2	−3.5	−0.2	−10.0±2.0
BH slice crosscourt	3%	−4.2	−3.7	−2.8	−10.7±2.9

Lean BH crosscourt: +4.2±2.1 per 100 returns v the current mix (2846 returns charted)

2nd serve to the forehand

Return	Now	Tour	Own	v Serena	Value
FH through the middle	51%	−3.2	+0.2	−0.9	−3.9±1.9
FH down the line	21%	−0.6	+0.8	+0.6	+0.8±4.1
FH crosscourt	19%	+0.5	+0.9	−3.0	−1.6±3.5
FH slice through the middle	6%	−15.2	−1.0	−0.4	−16.6±2.4
FH slice crosscourt	2%	−14.9	−1.6	±0.0	−16.6±2.4

Lean FH down the line: +4.4±3.5 per 100 returns v the current mix (778 returns charted)

2nd serve to the backhand

Return	Now	Tour	Own	v Serena	Value
BH through the middle	48%	−2.6	+0.1	−0.3	−2.8±1.3
BH crosscourt	20%	+1.5	−1.1	−0.2	+0.1±2.3
BH down the line	19%	−0.5	+1.7	−2.1	−0.9±3.6
FH through the middle	5%	−2.7	+1.6	−0.9	−2.0±2.1
FH inside-out	3%	+1.4	−1.1	+0.6	+0.8±3.8

Lean FH inside-out: +2.5±3.8 per 100 returns v the current mix (1462 returns charted, inside the 90% margin)

Serena Williams returning

1st serve to the forehand

Return	Now	Tour	Own	v Bianca	Value
FH through the middle	49%	+4.2	−2.6	−0.4	+1.1±1.2
FH crosscourt	36%	+5.3	−1.6	−0.7	+3.0±2.1
FH down the line	11%	+1.5	−0.4	−2.0	−0.8±3.0
BH through the middle	1%	+5.2	−3.4	−0.9	+0.9±2.1
FH slice through the middle	1%	−6.7	−0.7	+0.2	−7.2±1.9

Lean FH crosscourt: +1.5±1.5 per 100 returns v the current mix (2166 returns charted)

1st serve to the backhand

Return	Now	Tour	Own	v Bianca	Value
BH through the middle	48%	+6.0	+0.3	−0.9	+5.4±1.1
BH crosscourt	33%	+7.7	+1.3	−1.2	+7.9±1.8
BH down the line	12%	+2.2	+1.1	−4.7	−1.5±3.1
BH slice through the middle	3%	−6.2	−4.5	+0.1	−10.6±2.3
BH slice crosscourt	2%	−4.2	−2.8	−4.8	−11.7±2.9

Lean BH crosscourt: +3.5±1.3 per 100 returns v the current mix (1939 returns charted)

2nd serve to the forehand

Return	Now	Tour	Own	v Bianca	Value
FH crosscourt	43%	+0.5	−0.5	−3.4	−3.4±2.9
FH through the middle	37%	−3.2	−0.1	−0.5	−3.7±1.9
FH down the line	18%	−0.6	+5.3	−0.7	+4.1±4.2
BH inside-in	1%	+2.0	−1.4	−1.4	−0.9±2.5
BH through the middle	1%	−1.0	−0.2	−0.8	−2.0±1.5

Lean FH down the line: +6.2±3.8 per 100 returns v the current mix (750 returns charted)

2nd serve to the backhand

Return	Now	Tour	Own	v Bianca	Value
BH crosscourt	51%	+1.5	+0.9	−1.4	+0.9±1.9
BH through the middle	30%	−2.6	−1.8	−0.8	−5.2±1.6
BH down the line	17%	−0.5	+3.4	−3.0	−0.2±3.8
FH inside-in	1%	+0.7	+0.7	−3.4	−2.0±3.1
FH inside-out	1%	+1.4	+0.2	−0.7	+0.9±3.0

Lean BH crosscourt: +2.1±1.2 per 100 returns v the current mix (954 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.