WTA vs ATP: are there more upsets in women’s tennis?
· Pronocast
We often hear that women’s tennis is less predictable: more upsets, favourites falling earlier, draws that open up. Do the numbers confirm it? We took 38,071 ATP and WTA singles matches played between January 2022 and September 2026 (19,552 on the ATP, 18,519 on the WTA) and checked, for each, whether the Elo favourite won.
The answer is the opposite of the received idea: on the WTA, the favourite wins slightly more often than on the ATP.
The favourite wins more often on the WTA
On the ATP, the Elo favourite wins 64.5% of matches. On the WTA, 65.7%. The raw gap of 1.2 points is significant (z = 2.4): it is not chance. In 2024 for example, the favourite wins 66.6% on the WTA against 64.4% on the ATP. Across five years (2022 to 2026), the WTA is ahead four times: only 2022 goes the other way (63.6% on the ATP, 63.1% on the WTA).
| Year | ATP | WTA |
|---|---|---|
| 2022 | 63.6% | 63.1% |
| 2023 | 64.4% | 65.5% |
| 2024 | 64.4% | 66.6% |
| 2025 | 64.6% | 65.8% |
| 2026 (up to 22 September) | 65.8% | 67.4% |
The explanation: slightly less tight matches
The favourite does not win more on the WTA because players are more predictable in absolute terms, but because favourites there more often have a clear edge on paper. Elo gives a favourite at 70% or more in 39.2% of WTA matches, against 36.2% of ATP matches. In the 80%-and-above band the gap is most visible: 17.9% of WTA matches, against 15.5% on the ATP. The favourite’s median probability is 66.0% on the WTA and 65.1% on the ATP.
| Favourite announced at | ATP share of matches | WTA share of matches | Favourite wins, ATP | Favourite wins, WTA |
|---|---|---|---|---|
| 50 to 60% | 34.2% | 32.2% | 53.9% | 53.4% |
| 60 to 70% | 29.5% | 28.5% | 62.8% | 62.8% |
| 70 to 80% | 20.7% | 21.3% | 70.8% | 71.4% |
| 80% and above | 15.5% | 17.9% | 82.6% | 85.6% |
At equal probability, no difference
To know whether a woman player is really more or less safe than a man, you have to compare at equal probability. We compared each match with what the favourite usually wins for the same Elo probability, all ATP and WTA matches pooled. Result: the ATP favourite wins 0.2 point less than expected (z = −0.6), the WTA favourite 0.2 point more (z = +0.7). Neither is distinguishable from chance. Up to 80%, the favourite’s win rate differs by at most 0.6 point between the two tours.
In other words, a 65% favourite behaves the same way on the WTA and the ATP. The raw difference comes from how matches are distributed, not from the nature of the tour. Upsets are not more frequent among women: it is lopsided matches that are, a little.
A hint among the big favourites, to be handled with care
One band stands out, and we read it after seeing the total, among several splits: it is not a discovery, it is a hint. Among favourites at 80% and above, the ATP favourite wins 1.6 points less than expected (82.6%, z = −2.5) and the WTA favourite 1.5 points more (85.6%, z = +2.4). The biggest favourites would be a little safer among women, a little less among men. With 3,039 and 3,312 matches, the sample cannot say whether this will last; we do not keep it as a rule.
And on grass?
By surface, after seeing the total, grass is the only one where favourites disappoint on both tours. At equal probability, the ATP favourite wins 2.7 points less than expected there (62.8%, 2,110 matches, z = −2.7), the WTA favourite 1.6 points less (63.5%, 2,276 matches, z = −1.6, within chance). Hard courts (+0.3 and −0.1 point) and clay (+0.4 on the ATP, +1.3 on the WTA) do not stray from chance. Grass is the least frequent surface: there are fewer matches for a rating to form a precise view of it. For the surface detail, see our article on surfaces.
And at the Grand Slams?
Another received idea says best-of-five favours men or favourites. Our study on best-of-five shows the favourite wins 70.8% in men’s Grand Slams (five sets) against 70.5% for women (three sets): the effect is the Grand Slam’s, not the format’s.
What this changes when reading a prediction
- Do not rely on “it’s a WTA match, so it’s open”. At equal probability, a 65% favourite is as reliable on the WTA as on the ATP.
- Read the probability, not the tour. Among the biggest favourites (80% and above), the WTA gave 85.6% wins against 82.6% on the ATP: a hint, not a rule.
- Be wary of grass. Favourites disappoint there on both tours, by a wider margin than elsewhere.
- These figures are about Elo alone, not the Pronocast model, which relies on more than the rating (see our methodology).
Today’s predictions cover the ATP, WTA and Challenger tours, with each player’s probability; the verified results page shows the real accuracy. To compare with the Challenger, see the Challenger favourite.
Method
ATP and WTA singles matches, from 1 January 2022 to 22 September 2026, where both players had already played at least twenty matches: 38,071 matches, seen from the favourite’s side, meaning the player Elo gives at least 50% before the match. The raw gap between tours is judged by a two-proportion z test. At equal probability, the expected rate is the actual win rate observed for a given probability, in 2.5-point bands, over the whole ATP and WTA sample pooled, and the test is a z = (wins − expected) / square root of the sum of p(1 − p). The per-tour total is the figure read; the splits by probability band, surface and year were made after seeing it, and the gap for favourites at 80% and above (z near ±2.4) is to be read as one hint among several splits tested. The full script is kept with our data.
Frequently asked questions
- Is women’s tennis less predictable than men’s tennis?
- No. Across 38,071 singles matches, the Elo favourite wins 65.7% on the WTA and 64.5% on the ATP: a raw gap of 1.2 points, significant (z = 2.4), in favour of the women favourites. At equal probability, the ATP favourite wins 0.2 point less than expected and the WTA favourite 0.2 point more, with no difference distinguishable from chance.
- Why does the favourite win more often on the WTA?
- Because WTA matches are slightly more lopsided: Elo gives a favourite at 70% or more in 39.2% of matches, against 36.2% on the ATP, and at 80% or more in 17.9% of matches against 15.5%. The difference comes from how matches are distributed, not from the nature of the tour.
- Are upsets more frequent on certain surfaces?
- Grass is the only surface where favourites disappoint on both tours: at equal probability, −2.7 points on the ATP (2,110 matches) and −1.6 point on the WTA (2,276 matches, within chance). Hard courts and clay do not stray from chance. These splits were made after seeing the total.
- Are the biggest favourites safer among women?
- It is a hint, not a rule. Among favourites at 80% and above, the WTA favourite wins 85.6% (1.5 points more than expected) and the ATP favourite 82.6% (1.6 points less), with a z near 2.4 on both sides. The gap was read after several splits: it is not enough to conclude.
- Do these figures apply to the Pronocast model?
- No, they are about Elo alone. The Pronocast model relies on more than the rating: its method is detailed on the methodology page.
Other articles
- Tennis prediction algorithm: how an AI model actually worksWhat a tennis prediction model really receives, how it learns without cheating with time, and why its accuracy plateaus around the market’s.
- Elo in tennis: understanding the rating that predicts matchesWhy a rating designed for chess predicts a tennis match better than the ATP ranking, and which adjustments it needs to really work.
- Tennis odds and implied probability: what they really sayHow to read bookmaker odds, strip out the margin, and why the market stays the benchmark most models can’t durably beat.
- How to bet on tennis: bankroll, value betting and riskHow much to stake, what value really means, and why our own model lost 9% betting on its disagreements with the market.
- Clay, hard or grass: what the surface really changes in tennisAcross 36,210 matches, a player’s overall level predicts better than their record on the day’s surface, and grass is where favourites fall most often.
- Head-to-head in tennis: does the H2H really predict the winner?Across 38,123 matches, the head-to-head leader wins less often than the Elo favourite. But a record against the favourite really does count.
- Tennis fatigue and rest: do tired players really lose more?Stringing matches together is barely measurable. Returning after a month without playing is: nearly ten points of win probability less than Elo predicts.
- Indoor tennis: are favourites more reliable under a roof?Indoors, the favourite wins 64.9% of matches, against 65.0% on outdoor hard courts. A good indoor record mostly reflects a good player.
- Best of five in tennis: do favourites really win more?At the Slams, the ATP favourite wins 70.8% of matches, the WTA favourite 70.5% over three sets. What five sets really change, and what they don’t.
- Tennis Challenger vs ATP: are favourites less reliable?The favourite wins 64.0% of men’s Challenger matches and 64.5% on the ATP Tour. At equal probability we measure no gap: what Challenger changes, and what it doesn’t.
- Tennis winning streaks: do players on a run win more?A player on five straight wins takes 56.9% of their matches where Elo expected 60.3%. What a winning streak tells you, and what it doesn’t.
- Does a 70% tennis favourite win 70% of the time?The favourite Elo puts at 70% or more wins 76.9% of matches, against 80.0% announced. How to read a prediction probability without being misled.
- Tennis surface change: are players really penalised?With global Elo, a player switching surface wins 3.6 points less than expected. With surface Elo, the gap disappears: what that changes for a prediction.