Win probability

Wednesday, 2 September 2026

20 matches selected · 2 tournaments · model last ran 01:50 UTC

Umpiry rates 20 matches on Wednesday, 2 September 2026. The closest is Alex Michelsen v Brandon Nakashima at 51 % — the model’s most uncertain call of the day. The most one-sided is Alexander Zverev v Lorenzo Sonego at 95 %. 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
18:00US Open
ATP · hard
R64Michelsen A.Nakashima B.51 %49 %Toss-up1–0
19:30US Open
ATP · hard
R128Giron M.Buse I.52 %48 %Toss-up0–2
02:25US Open
WTA · hard
R64Vekic D.Li A.52 %48 %Toss-up0–2
00:15US Open
WTA · hard
R64Alexandrova E.Birrell K.52 %48 %Toss-up2–0
01:20US Open
ATP · hard
R128Bonzi B.Molcan A.52 %48 %Toss-up1–0
20:00US Open
ATP · hard
R128Marozsan F.Zheng M.52 %48 %Toss-up0–2
18:00US Open
ATP · hard
R64Rinderknech A.Munar J.53 %47 %Toss-up2–1
20:00US Open
WTA · hard
R64Navarro E.Mcnally C.57 %43 %Toss-up3–2
21:40US Open
ATP · hard
R64Shapovalov D.Van Assche L.60 %40 %Slight edge2–0
02:00US Open
ATP · hard
R128Monfils G.Vallejo A.60 %40 %Slight edge1–0
18:00US Open
ATP · hard
R64Rublev A.Merida Aguilar D.61 %39 %Slight edge0–1
01:20US Open
ATP · hard
R64Vacherot V.Majchrzak K.63 %37 %Slight edge1–0
23:20US Open
WTA · hard
R64Kalinskaya A.Yu Wang X.64 %36 %Slight edge4–1
18:00US Open
WTA · hard
R64Shnaider D.Pliskova K.65 %35 %Slight edge2–0
20:00US Open
ATP · hard
R64Shelton B.Hurkacz H.68 %32 %Clear favourite1–0
19:30US Open
ATP · hard
R128Svajda Z.Altmaier D.71 %29 %Clear favourite1–2
18:00US Open
WTA · hard
R64Cirstea S.Parry D.73 %27 %Clear favourite1–0
02:00US Open
WTA · hard
R128Gauff C.Sonmez Z.87 %13 %Strong favourite1–0
20:00US Open
ATP · hard
R128De Minaur A.Guerrieri A.88 %12 %Strong favourite1–0
03:30US Open
ATP · hard
R128Zverev A.Sonego L.95 %5 %Strong favourite8–0

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, 1 September 2026 · 20 matches

Favourites won

17 / 20

Model expected

14.6

The model expected 14.6 favourites to win; 17 did. See yesterday’s page.

Biggest shock, last 7 days

1 Sept
US Open
WTA · hard
R128

Surprise score

83

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.