RallyIQ

Game plan

Sara Errani v Petra Kvitova

Every number combines what Sara Errani does well with what Petra Kvitova allows, each measured against the tour average and shrunk toward it when the sample is thin. Flip perspective

Forecast

Sara Errani wins, best of 3 1%90%: 0%–10% · best of 5: 0%
Serve points won 46.7% / 64.0% Sara / Petra · tour 58.1%
Strengths only, no similarity priors 1%serve 46.7% / 64.0%

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 At least one of them is no longer active or has too little charted in the last three seasons, so both are compared on their careers.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 Sara Errani's record against Petra Kvitova's tactical lookalikes and in their charted head-to-heads. 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

CareerSaraPetra
Direction choice−0.23 ±0.11
better than 14%
+0.13 ±0.04
better than 77%
Shot selection−0.34 ±0.17
better than 19%
+0.33 ±0.07
better than 82%
Execution+1.67 ±0.48
better than 97%
−0.96 ±0.32
better than 18%
Points left on the table2.62 ±0.13
lower than 48%
3.00 ±0.06
lower than 11%

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: Sara Errani −0.07, Petra Kvitova +0.77. 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.

Sara Errani serving

Deuce court

1st serveNowSara winsv PetraMatchupOptimal
Wide35%54%66%53.8%±5.935%
Body45%50%57%49.5%±5.630% ▼
T20%53%68%52.8%±6.935% ▲

Optimal v Petra Kvitova: +0.6±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.

Ad court

1st serveNowSara winsv PetraMatchupOptimal
Wide37%54%67%55.8%±5.627% ▼
Body46%53%58%55.1%±5.641% ▼
T17%53%64%52.9%±8.132% ▲

Optimal v Petra Kvitova: +0.2±0.8 per 100 first serves (faults included) over the current mix, inside the 90% margin. Serving wide every time would read +0.8 per 100 first serves in before the returner adjusts.

Petra Kvitova serving

Deuce court

1st serveNowPetra winsv SaraMatchupOptimal
Wide42%72%60%67.4%±5.248% ▲
Body12%57%66%65.3%±7.60% ▼
T46%66%64%61.2%±5.952% ▲

Optimal v Sara Errani: +0.2±0.7 per 100 first serves (faults included) over the current mix, inside the 90% margin. Serving wide every time would read +3.1 per 100 first serves in before the returner adjusts.

Ad court

1st serveNowPetra winsv SaraMatchupOptimal
Wide54%71%58%63.6%±5.647% ▼
Body8%54%54%52.0%±8.80% ▼
T38%73%69%76.8%±4.753% ▲

Optimal v Sara Errani: +1.4±0.7 per 100 first serves (faults included) over the current mix. Serving T every time would read +9.2 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.

Sara Errani returning

1st serve to the forehand

ReturnNowTourOwnv PetraValue
FH through the middle42%+4.2+2.7−1.9+4.9±2.2
FH down the line23%+1.5+4.7−5.1+1.1±4.1
FH crosscourt16%+5.3+0.6−0.2+5.7±3.8
FH slice through the middle13%−6.7+0.5−2.0−8.2±2.4
FH slice down the line6%−10.5−0.1−3.7−14.3±3.3

Lean FH crosscourt: +4.4±3.5 per 100 returns v the current mix (394 returns charted)

1st serve to the backhand

ReturnNowTourOwnv PetraValue
BH through the middle37%+6.0+1.9+0.8+8.8±2.1
BH crosscourt34%+7.7+1.5+2.7+11.9±2.9
BH slice through the middle13%−6.2+1.7−2.8−7.3±2.3
BH slice crosscourt7%−4.2−0.1+0.2−4.1±2.8
BH slice down the line5%−12.5+0.5−2.3−14.3±3.4

Lean BH crosscourt: +6.4±2.1 per 100 returns v the current mix (315 returns charted)

2nd serve to the forehand

ReturnNowTourOwnv PetraValue
FH through the middle45%−3.2+2.0−1.0−2.1±2.6
FH crosscourt30%+0.5+0.3+1.0+1.9±4.2
FH down the line26%−0.6+0.9−5.1−4.7±4.9

Lean FH crosscourt: +3.5±3.4 per 100 returns v the current mix (94 returns charted)

2nd serve to the backhand

ReturnNowTourOwnv PetraValue
BH crosscourt55%+1.5+1.4−2.8+0.1±3.0
BH through the middle29%−2.6+0.5−2.3−4.4±2.2
FH inside-out8%+1.4+0.6−5.1−3.1±3.6
FH through the middle4%−2.7+0.3−1.0−3.4±1.7
BH down the line3%−0.5−0.6−3.7−4.8±3.6

Lean BH crosscourt: +1.9±1.5 per 100 returns v the current mix (146 returns charted)

Petra Kvitova returning

1st serve to the forehand

ReturnNowTourOwnv SaraValue
FH through the middle49%+4.2−1.4+0.5+3.3±2.1
FH crosscourt25%+5.3−0.7+6.0+10.7±3.3
FH down the line19%+1.5−5.1+5.9+2.4±3.7
FH slice through the middle4%−6.7−0.1+0.1−6.7±2.1
FH slice crosscourt1%−6.6−0.6±0.0−7.3±1.7

Lean FH crosscourt: +6.2±2.8 per 100 returns v the current mix (1275 returns charted)

1st serve to the backhand

ReturnNowTourOwnv SaraValue
BH through the middle47%+6.0−1.9+1.7+5.8±1.8
BH crosscourt26%+7.7−2.2+6.9+12.5±2.9
BH down the line13%+2.2±0.0+4.0+6.1±3.5
BH slice through the middle7%−6.2+0.2+0.7−5.3±2.0
BH slice crosscourt3%−4.2−4.5±0.0−8.7±2.2

Lean BH crosscourt: +6.5±2.3 per 100 returns v the current mix (1499 returns charted)

2nd serve to the forehand

ReturnNowTourOwnv SaraValue
FH crosscourt43%+0.5−0.4+7.1+7.2±4.0
FH through the middle37%−3.2−4.5−0.9−8.5±2.9
FH down the line20%−0.6−1.3+3.9+2.0±5.1

Lean FH crosscourt: +6.8±2.7 per 100 returns v the current mix (419 returns charted)

2nd serve to the backhand

ReturnNowTourOwnv SaraValue
BH through the middle44%−2.6+0.5−0.5−2.6±2.4
BH crosscourt41%+1.5+1.2+3.4+6.0±3.2
BH down the line15%−0.5+1.0+0.3+0.8±5.2
BH slice through the middle1%−11.7−0.7±0.0−12.4±1.0

Lean BH crosscourt: +4.7±2.3 per 100 returns v the current mix (593 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.

Sara Errani

Favour

ShotEdgeOwnTheirs
FH to their backhand · return+5.3±4.6+2.4+2.9
FH to the middle · serve +1+3.3±2.7+2.9+0.4
FH to their forehand · serve +1+2.6±4.1+3.0−0.4
BH to their backhand · serve +1+2.6±4.6+4.8−2.2
FH to the middle · return+2.5±2.6+1.9+0.6
FH to the middle · rally+2.0±3.0+2.5−0.5

Avoid

ShotEdgeOwnTheirs
BH slice to their backhand · rally−5.7±2.7−0.3−5.4
BH to their backhand · rally−5.1±4.3−0.2−4.9
BH to their backhand · return +1−3.3±3.8+3.2−6.5
FH to their backhand · return +1−2.8±4.6+0.4−3.2
BH slice to their forehand · rally−1.9±4.0−1.3−0.6

Petra Kvitova

Favour

ShotEdgeOwnTheirs
BH to their forehand · return+15.4±4.5+7.6+7.7
FH to their backhand · return+14.4±5.2+3.8+10.6
FH to their forehand · return+8.4±4.2+1.8+6.6
BH to their backhand · return+7.4±3.7+2.6+4.8
BH to their forehand · rally+6.4±4.9+0.9+5.6
BH to their forehand · serve +1+5.5±5.0+2.0+3.5

Avoid

ShotEdgeOwnTheirs
FH to the middle · serve +1−6.0±2.9−4.8−1.3
BH slice to the middle · rally−6.0±2.6−5.0−1.0
BH slice to their backhand · rally−4.8±2.7−4.5−0.3
BH to the middle · return +1−4.7±2.8−3.8−0.9
FH to the middle · rally−2.9±3.1−4.4+1.5

Against Petra Kvitova-like opponents

Sara Errani vMatchesServe pts wonReturn pts won
All charted opponents–47.3%44.7%

Similar by tactical fingerprint: Elena Rybakina, Madison Keys, Amanda Anisimova, Talia Gibson, Barbora Krejcikova, Dayana Yastremska, Anastasia Pavlyuchenkova, Aliaksandra Sasnovich, Anett Kontaveit, Johanna Konta. When two players have rarely met, their records against these lookalikes fill the gap.