Win probability

Wednesday, 12 August 2026

8 matches selected · 5 tournaments · model last ran 14:50 UTC

Umpiry rates 8 matches on Wednesday, 12 August 2026. The closest is Nikolas Sanchez Izquierdo v Maxim Mrva at 51 % — the model’s most uncertain call of the day. The most one-sided is Learner Tien v Daniel Merida Aguilar at 72 %. Probabilities come from a per-tour model trained on Elo, surface Elo, recent serve and return form and layoff.

Rated matches · ordered closest first
TimeTournamentRoundMatchProbabilityVerdictH2H
15:40Todi
CHALLENGER · clay
R16Sanchez Izquierdo N.Mrva M.51 %49 %Toss-up1–1
08:40Hamburg
CHALLENGER · clay
R16Dietrich D.Sachko V.53 %47 %Toss-up1–0
22:10Montreal
ATP · hard
QFShelton B.Mensik J.53 %47 %Toss-up2–2
13:15Astana
CHALLENGER · hard
R16Zhukayev B.Alkaya M.54 %46 %Toss-up0–1
06:05Astana
CHALLENGER · hard
R16Sultanov K.Ratti L.58 %42 %Toss-up1–0
23:10Toronto
WTA · hard
QFGauff C.Bencic B.63 %37 %Slight edge6–2
23:40Toronto
WTA · hard
QFRybakina E.Osaka N.65 %35 %Slight edge2–0
23:45Montreal
ATP · hard
QFTien L.Merida Aguilar D.72 %28 %Clear favourite1–0

How to read this

Each row gives the model’s probability that the favourite wins, and the verdict says the same thing in words. Rows are ordered by how close the model thinks the match is, so the top of the table is where it is least sure. A 70 % favourite losing is not a broken model — it is the 30 %. Probabilities are not odds and take no account of any market.

How often the model has been right

Umpiry win-probability model accuracy by tour family, measured on the predictions the model made
TourCorrect
ATP / WTA66 %
Challenger (men)64 %
Challenger (women)68 %
ITF (men)66 %
ITF (women)64 %

Measured on the predictions the model actually made, not on a backtest — see Methodology.

Yesterday

Tuesday, 11 August 2026 · 9 matches

Favourites won

7 / 9

Model expected

5.4

The model expected 5.4 favourites to win; 7 did. See yesterday’s page.

Biggest shock, last 7 days

11 Aug
Cincinnati
WTA · hard
Q64

Surprise score

88

Questions

How is the probability calculated?
A separate model for each tour, trained on Elo, surface-specific Elo, recent serve and return form and time since the player’s last match. It runs several times a day; the time of the last run is at the top of this page.
How often is the model right?
We publish it. The table above gives the hit rate for each tour family, measured on the predictions the model actually made — see Methodology for how it is computed.
Why are the closest matches at the top?
Rows are ordered by distance from 50 %, so the table opens where the model is least sure. “Most one-sided” reverses the order and groups the rows by tournament.
Is this a betting tip?
No. The page shows a model’s probability and how often that model has been right. There are no odds, no comparison with a market and no suggested stake.