Win probability

Sunday, 30 August 2026

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

Umpiry rates 20 matches on Sunday, 30 August 2026. The closest is Kamil Majchrzak v Hamad Medjedovic at 50 % — the model’s most uncertain call of the day. The most one-sided is Jessica Pegula v Elena Gabriela Ruse at 89 %. 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
R128Majchrzak K.Medjedovic H.50 %50 %Toss-up2–2
21:00US Open
ATP · hard
R128Brooksby J.Faria J.50 %50 %Toss-up1–2
23:00US Open
WTA · hard
R128Kessler M.Alexandrova E.51 %49 %Toss-up0–2
23:30US Open
WTA · hard
R128Birrell K.Marcinko P.51 %49 %Toss-up2–1
18:00US Open
WTA · hard
R128Iatcenko P.Zarazua R.52 %48 %Toss-up1–0
22:00US Open
WTA · hard
R128Pliskova K.Vandewinkel H.56 %44 %Toss-up1–0
18:00US Open
WTA · hard
R128Gibson T.Vekic D.57 %43 %Toss-up0–1
18:00US Open
ATP · hard
R128Merida Aguilar D.Fucsovics M.59 %41 %Slight edge1–1
21:00US Open
ATP · hard
R128Munar J.Atmane T.61 %39 %Slight edge1–0
19:30US Open
ATP · hard
R128Norrie C.Van Assche L.62 %38 %Slight edge3–2
23:00US Open
ATP · hard
R128Shapovalov D.Kecmanovic M.62 %38 %Slight edge7–0
18:00US Open
ATP · hard
R128Wu Y.Walton A.63 %37 %Slight edge1–0
23:00US Open
ATP · hard
R128Sakamoto R.Vukic A.64 %36 %Slight edge1–1
23:30US Open
WTA · hard
R128Preston T.Parks A.65 %35 %Slight edge1–0
18:00US Open
ATP · hard
R128Prizmic D.Shevchenko A.74 %26 %Clear favourite1–0
18:00US Open
WTA · hard
R128Paolini J.Erjavec V.75 %25 %Clear favourite1–0
18:00US Open
ATP · hard
R128Lehecka J.Carreno Busta P.80 %20 %Strong favourite2–1
20:30US Open
ATP · hard
R128Medvedev D.Gaston H.85 %15 %Strong favourite2–0
19:30US Open
ATP · hard
R128Paul T.Wong C.88 %12 %Strong favourite1–0
19:05US Open
WTA · hard
R128Pegula J.Gabriela Ruse E.89 %11 %Strong 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

Saturday, 29 August 2026 · 16 matches

Favourites won

9 / 16

Model expected

9.0

The model expected 9.0 favourites to win; 9 did. See yesterday’s page.

Biggest shock, last 7 days

27 Aug
Kingston 2
CHALLENGER · hard
QF

Surprise score

86

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.