Win probability

Wednesday, 19 August 2026

20 matches selected · 5 tournaments · model last ran 18:50 UTC

Umpiry rates 20 matches on Wednesday, 19 August 2026. The closest is Sumit Nagal v Jan Kumstat at 51 % — the model’s most uncertain call of the day. The most one-sided is Aryna Sabalenka v Xiyu Wang at 92 %. 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
10:00Prague
CHALLENGER · clay
R16Nagal S.Kumstat J.51 %49 %Toss-up0–2
17:10Cincinnati
WTA · hard
R16Andreeva M.Kostyuk M.52 %48 %Toss-up1–3
08:10Sion
CHALLENGER · clay
R16Nijboer R.Compagnucci T.52 %48 %Toss-up0–1
09:55Sion
CHALLENGER · clay
R16Marti Pujolras A.Kuzmanov D.52 %48 %Toss-up0–1
19:25Kingston
CHALLENGER · hard
R16Winter E.Bueno G.53 %47 %Toss-up0–1
09:50Prague
CHALLENGER · clay
R16Krutykh O.Hardt N.54 %46 %Toss-up1–1
09:40Prague
CHALLENGER · clay
R16Bautista Torres J.Hsin Tseng C.54 %46 %Toss-up1–1
19:00Cincinnati
WTA · hard
R16Anisimova A.Noskova L.55 %45 %Toss-up3–1
15:15Kingston
CHALLENGER · hard
R16Ymer E.Glinka D.57 %43 %Toss-up0–1
00:20Cincinnati
ATP · hard
R32Tien L.Tiafoe F.57 %43 %Toss-up1–2
19:25Cincinnati
ATP · hard
R16Fils A.De Minaur A.63 %37 %Slight edge2–2
15:10Cincinnati
ATP · hard
R16Jodar R.Cobolli F.64 %36 %Slight edge0–1
01:00Cincinnati
WTA · hard
R32Jovic I.Bouzkova M.65 %35 %Slight edge0–1
17:10Cincinnati
ATP · hard
R16Mensik J.Tirante T.74 %26 %Clear favourite0–1
23:10Cincinnati
ATP · hard
R32Auger Aliassime F.Cerundolo J.75 %25 %Clear favourite1–1
17:00Cincinnati
WTA · hard
R16Pegula J.Cirstea S.75 %25 %Clear favourite4–1
18:05Cincinnati
ATP · hard
R16Zverev A.Paul T.76 %24 %Clear favourite1–3
19:40Cincinnati
WTA · hard
R16Rybakina E.Shnaider D.78 %22 %Clear favourite2–0
15:10Cincinnati
WTA · hard
R16Swiatek I.Parry D.89 %11 %Strong favourite2–0
23:10Cincinnati
WTA · hard
R32Sabalenka A.Wang X.92 %8 %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

Tuesday, 18 August 2026 · 20 matches

Favourites won

16 / 20

Model expected

15.3

The model expected 15.3 favourites to win; 16 did. See yesterday’s page.

Biggest shock, last 7 days

18 Aug
M25 Lesa
ITF · clay
R32

Surprise score

85

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.