Win probability

Thursday, 27 August 2026

20 matches selected · 4 tournaments · model last ran 20:50 UTC

Umpiry rates 20 matches on Thursday, 27 August 2026. The closest is Ignacio Buse v Juan Manuel Cerundolo at 50 % — the model’s most uncertain call of the day. The most one-sided is Liam Draxl v Andrew Johnson at 84 %. 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
23:00Winston-Salem
ATP · hard
QFBuse I.Cerundolo J.50 %50 %Toss-up1–2
18:00US Open
ATP · hard
Q32Rincon D.Barrios Vera T.51 %49 %Toss-up0–1
01:50US Open
ATP · hard
Q64Schoolkate T.Chan Hong S.54 %46 %Toss-up1–2
00:30Monterrey
WTA · hard
R16Vidmanova D.Bucsa C.55 %45 %Toss-up1–1
18:00US Open
ATP · hard
Q32Dougaz A.Guerrieri A.55 %45 %Toss-up0–2
06:00Monterrey
WTA · hard
R16Tauson C.Alexandrova E.55 %45 %Toss-up3–0
23:35US Open
ATP · hard
Q64Budkov Kjaer N.O'Connell C.55 %45 %Toss-up0–1
18:00US Open
ATP · hard
Q32Wong C.Lajovic D.57 %43 %Toss-up1–0
21:35US Open
ATP · hard
Q32Dimitrov G.Virtanen O.57 %43 %Toss-up
18:00US Open
WTA · hard
Q64Andrea Knutson G.Gorgodze E.58 %42 %Slight edge1–0
18:00US Open
WTA · hard
Q64Pareja J.Stefanini L.60 %40 %Slight edge2–1
00:25US Open
ATP · hard
Q64Harris L.Rocha H.61 %39 %Slight edge1–0
23:30US Open
ATP · hard
Q64Gaston H.Ilagan A.62 %38 %Slight edge1–0
18:00US Open
WTA · hard
Q64Iatcenko P.Lazaro Garcia A.64 %36 %Slight edge2–1
22:45US Open
ATP · hard
Q64Sakamoto R.Muller A.65 %35 %Slight edge2–1
01:50US Open
ATP · hard
Q64Kym J.Smith C.68 %32 %Clear favourite0–1
00:25US Open
ATP · hard
Q64Llamas Ruiz P.Sachko V.72 %28 %Clear favourite1–0
18:00US Open
ATP · hard
Q32Samuel T.Garin C.73 %27 %Clear favourite1–0
18:00US Open
WTA · hard
Q64Montgomery R.Branstine C.76 %24 %Clear favourite1–1
01:05US Open
ATP · hard
Q64Draxl L.Johnson A.84 %16 %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

Wednesday, 26 August 2026 · 20 matches

Favourites won

10 / 20

Model expected

11.3

The model expected 11.3 favourites to win; 10 did. See yesterday’s page.

Biggest shock, last 7 days

26 Aug
W75 Bytom
ITF · clay
R32

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.