Win probability

Tuesday, 1 September 2026

20 matches selected · 2 tournaments · model last ran 21:50 UTC

Umpiry rates 20 matches on Tuesday, 1 September 2026. The closest is Darja Vidmanova v Jessica Bouzas Maneiro at 52 % — the model’s most uncertain call of the day. The most one-sided is Aryna Sabalenka v Maria Camila Osorio Serrano at 94 %. 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
23:50US Open
WTA · hard
R128Vidmanova D.Bouzas Maneiro J.52 %48 %Toss-up0–1
19:30US Open
WTA · hard
R128Sakkari M.Montgomery R.52 %48 %Toss-up1–0
23:20US Open
WTA · hard
R128Badosa P.Kasatkina D.53 %47 %Toss-up4–4
18:00US Open
WTA · hard
R128Potapova A.Valentova T.55 %45 %Toss-up
20:30US Open
ATP · hard
R128Lennard Struff J.Ugo Carabelli C.63 %37 %Slight edge1–0
18:30US Open
WTA · hard
R128Keys M.Korneeva A.64 %36 %Slight edge1–0
21:00US Open
ATP · hard
R128Jodar R.Kokkinakis T.68 %32 %Clear favourite
03:30US Open
ATP · hard
R128Tiafoe F.Damm M.69 %31 %Clear favourite2–0
23:00US Open
ATP · hard
R128Tien L.Borges N.72 %28 %Clear favourite3–0
23:20US Open
ATP · hard
R128Musetti L.Fery A.72 %28 %Clear favourite1–0
18:00US Open
ATP · hard
R128Cobolli F.Comesana F.73 %27 %Clear favourite2–0
02:00US Open
ATP · hard
R128Shelton B.Griekspoor T.75 %25 %Clear favourite1–0
21:00US Open
ATP · hard
R128Shang J.Trungelliti M.76 %24 %Clear favourite0–1
18:00US Open
ATP · hard
R128Ruud C.Cerundolo J.80 %20 %Clear favourite1–2
02:00US Open
WTA · hard
R128Swiatek I.Wang X.84 %16 %Strong favourite3–0
23:00US Open
ATP · hard
R128Auger Aliassime F.Hijikata R.85 %15 %Strong favourite1–0
20:00US Open
ATP · hard
R128Fritz T.Blanch D.88 %12 %Strong favourite1–0
20:30US Open
WTA · hard
R128Andreeva M.Tjen J.90 %10 %Strong favourite2–0
19:30US Open
WTA · hard
R128Rybakina E.Frodin T.94 %6 %Strong favourite1–0
18:30US Open
WTA · hard
R128Sabalenka A.Camila Osorio Serrano M.94 %6 %Strong favourite2–0

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

Monday, 31 August 2026 · 20 matches

Favourites won

14 / 20

Model expected

13.3

The model expected 13.3 favourites to win; 14 did. See yesterday’s page.

Biggest shock, last 7 days

30 Aug
US Open
ATP · hard
R128

Surprise score

92

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.