For years, the narrative around the WTA Tour has been one of drama and unpredictability. Gradually though – and something this year has reaffirmed – consistency is becoming the order of the day in women’s tennis.

Overall in 2023, 69.4% of matches on the WTA Tour were won by the pre-match favourite (1,570/2,262) according to Opta’s Win Probability Model, an improvement of +1.5% compared to 2022. Out of the 27 finals in 2023 with a pre-match favourite holding a win probability of 60% or higher, the favourite won on 16 occasions. Three of those final victories for the underdog came at WTA 1000 events – Dubai, Indian Wells, and Madrid – with another being Marketa Vondrousova’s triumph over Ons Jabeur at Wimbledon.

Caroline Garcia’s win at last year’s WTA Finals in Fort Worth served as a shock culmination to 2022, with the underdog winning 11 of the 15 matches at the Finals, for an upset rate of 73.3%.

This year’s season-ender was much more reflective of improved consistency at the top of the WTA hierarchy. Of the 14 matches with a clear favourite pre-match, 12 were eventually won by that favourite for a win rate of 85.7%. The only encounter with a 50-50 split win probability pre-match was the round robin on the opening night between Aryna Sabalenka and Maria Sakkari, which the then-top-ranked Sabalenka won 6-0 6-1.

The 85.7% win rate for favourites in Cancun was still only the fifth-highest percentage at events on the WTA Tour in 2023, with Guangzhou holding the highest at 92.9%. Meanwhile, at this year’s four grand slam events, the fallout went largely according to form, with the pre-match favourite winning 75.8% of the time. The US Open had the highest win rate at 83.3%, while the first slam of the year had the lowest, with the Australian Open holding a comparative win rate of 73%.

WTA 2023 - Wins as Favourite (Min. 20+ games)

According to Opta’s Win Probability model however, the biggest upset on the WTA Tour in 2023 did come at Melbourne Park, via American qualifier Katie Volynets’ victory over ninth seed Veronika Kudermetova in the second round.

Volynets had a pre-match win probability of just 10.6%, which only rose to 13.6% after winning the opening set. Despite Kudermetova taking the second set 6-2 and conventional logic pointing towards her eventual victory, Volynets’ chance of winning actually went up to 21.8% coming into the deciding set.

Kudermetova eventually got some of her own back in September, claiming victory as an 11.9% underdog against Iga Swiatek on the way to eventual tournament victory in Tokyo.

Kudermetova ended 2023 with the highest win % on the WTA Tour as the pre-match underdog, among those with a minimum of 10 such matches, winning 57.1% of the time.

Among that sample, only seven players finished with a win rate of 50% or higher – Kudermetova, Anastasia Potapova (who also finished with a similar rate of 57.1% in 2022), Liudmila Samsonova, Rebeka Masarova and Donna Vekic along with two on 50%, Anhelina Kalinina and Elina Svitolina.

WTA 2023 - Wins as underdog

Swiatek was the defending champion coming into the US Open, but lost to Jelena Ostapenko in the fourth round, despite going one set up (at which point the Opta supercomputer gave her a 93% chance of winning).

Despite that upset, 2023 was ultimately the Pole’s year. Swiatek won 87.1% of matches where she was the favourite, and among players on the WTA Tour with a minimum of 20 such matches, trailed only one player – her opponent in the Roland-Garros final, Karolina Muchova (89.3%).

Claiming 61 victories, Swiatek was the only player on the WTA Tour this year to have won more than 50 matches in 2023 as the pre-match favourite, with Sabalenka the next best at 49.

En route to taking the WTA’s No. 1 ranking from Sabalenka, Swiatek ultimately proved a supreme frontrunner. In what was essentially the showdown for the WTA’s year-end #1 ranking, Swiatek was the 68.8% favourite coming into the semi-final against Sabalenka according to our model. After taking the opening set 6-3, the 22-year-old’s chances of winning shot up to 86.8%.

Swiatek conceded the fewest games at the WTA Finals since the round-robin format was reintroduced in 2003, at just 20 games, smashing Serena Williams’ previous record of 32 set in 2012. Swiatek’s win probability after taking the opening set in Cancun never went below 80%, with her lowest coming against Jessica Pegula in the final – 84.5%.

WTA 2023 - Wins as Favourite

Opta’s Live Win Probability Model enables us to determine the key moments when tournaments and matches are won or lost, predicting the likelihood of either player winning a set or match in any given scenario.

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