Sunday's start of fourth round in the US Open women's draw will deliver clashes that will shape the second week of the tournament. Defending champion Aryna Sabalenka faces surprise package Cristina Bucsa, who stunned 19th seed Elise Mertens in the third round. The American crowd will rally behind Taylor Townsend, who shocked with defeating world No. 5 Mirra Andreeva and dreams of another upset. Barbora Krejcikova comes back to contention with setting upsets after few months of absence. The bottom half of the draw also features matchups between former Grand Slam champions - Elena Rybakina takes on Marketa Vondrousova, while Jessica Pegula meets Ann Li in an all-American showdown.
Sabalenka vs. Bucsa
Defending champion and top seed Aryna Sabalenka enters the fourth round as the overwhelming favorite against world No. 95 Cristina Bucsa. The Belarusian has been impressive in New York - she hasn't dropped a set, defeating Rebeka Masarova 7-5, 6-1, Polina Kudermetova 7-6(4), 6-2, and Leylah Fernandez 6-3, 7-6(2). That match was not a cakewalk despite the straight set victory, as the Canadian pushed her with 19 pressure points created on Sabalenka's serve. The Belarusian was super efficient though, winning in straights despite creating just 9 pressure points on return and sealed the victory with a tiebreak win in second set. Apart of all the obvious brilliance of the world number one, particularly impressive is her tiebreak play - Sabalenka has won 21 of 22 tiebreaks played this season, with her current streak standing at 18 consecutive wins since February when she lost to Ekaterina Alexandrova in Doha.
The Spaniard is experiencing the Grand Slam run of her life. Cristina Bucsa delivered one of the biggest surprises of the third round, eliminating Elise Mertens after a three-set battle 3-6, 7-5, 6-3. She previously defeated Claire Liu 6-2, 6-1 and Alexandra Eala 6-4, 6-3. The victory against the 19 years-old from Phillipines was already a notable surprise, but her win against Mertens was rated as a really strong upset rated with a pre-match odd 5.35. For the 27-year-old, this marks her first advancement to the second week of a Grand Slam tournament. Bucsa displays solid defensive tennis combined with point construction skills and sudden attacks, which has troubled higher-seeded opponents throughout this tournament.
Sabalenka and Bucsa have never faced each other on the main WTA tour. The Belarusian boasts a 75% win rate on hard courts in 2025 and hasn't dropped a set at this year's US Open. Any competitive contest between both will be a surprise and another upset is less than likely to happen, looking at the performance discrepancy.
Rybakina vs. Vondrousova
World No. 10 Elena Rybakina faces former Wimbledon champion Marketa Vondrousova in what promises to be one of the most evenly matched fourth-round encounters. The Kazakhstani reached this stage after convincing victories over Tereza Valentova 6-3, 7-6(7) and dominating Emma Raducanu 6-1, 6-2. The match which was supposed to be a hit of third round ended up with a complete demolishion, showing the roof of the Kazakh's abilities and her ambitions to be one of the top contenders after a very promising results in the summer. Rybakina has advanced to the US Open fourth round for the first time in her seventh main-draw appearance and completes her collection of second-week appearances at all four Grand Slams.
Marketa Vondrousova pulled off an upset in the third round, eliminating seventh seed Jasmine Paolini 7-6(4), 6-1. The Italian had not much to tell in this match, producing just two breakpoints - both cleared by the Wimbledon champ fro 2023. The Czech previously defeated Oksana Selekhmeteva 6-3, 7-6(3) and McCartney Kessler 7-6(7), 6-2. For the 26-year-old from Prague, this marks her first advancement to a Grand Slam fourth round since Roland Garros 2024, where she reached the semifinals. Vondrousova maintains a perfect 3-0 record against Paolini, and her victory was also her 15th career win over a Top 10 player.
The head-to-head between Rybakina and Vondrousova stands at 1-1. They last met in Rome 2023, where Rybakina won 6-3, 6-3. Previously in Moscow 2021, Vondrousova prevailed 6-4, 6-4. Rybakina has shown excellent form this summer - she returned to the Top 10 in early August and is seeking for the breakthrough result after three consecutive semifinals run in Washington, Montrela and Cincinnati. Vondrousova excels her comeback after the first part of the season being naggled by injury issues, showing her abilities to compete against the top players. The question is, how she handles against Rybakina's storming and efficient serve performance - which is reflected in the stats as the best serving performance in the field right now.
Pegula vs. Li
Last year's finalist Jessica Pegula, faces compatriot Ann Li in a battle for the quarterfinals. The world No. 4 hasn't dropped a set in this year's tournament, defeating Mayar Sherif 6-0, 6-4, Anna Blinkova 6-1, 6-3, and Victoria Azarenka 6-1, 7-5. Pegula has passed the test against the experienced veteran, in a match which could end up even earlier - the American produced 15 breakpoints, converting "just" 6 of them, but was the superior force during whole the match.
Ann Li is experiencing the best Grand Slam tournament of her career. The American defeated Rebecca Sramkova 4-6, 6-2, 6-4, upset 16th seed Belinda Bencic 6-3, 6-3, and won the third round encounter between two underdogs who made the most of the upset opportunities - she defeated Priscilla Hon 7-5, 6-3. For the 25-year-old, this marks her first advancement to the US Open fourth round, beating her previous best from 2020, when she approached third round.
Pegula and Li have met twice, splitting their matches (1-1). Their last encounter was in the second round of Roland Garros 2025, where Pegula won 6-3, 7-6(3). Previously, Li triumphed on hard courts, but this happened in 2018 on ITF circuit, when both were completely different players than today. Since the start of 2021, Pegula has amassed 32 hard-court major wins - third most among women behind Sabalenka (51) and Swiatek (36). The draw has opened up for Pegula after the eliminations of Emma Navarro and Mirra Andreeva, so the opportunity to replicate the last year's great run is definitely on.
Krejcikova vs. Townsend
Two-time Grand Slam champion Barbora Krejcikova faces the sensational Taylor Townsend in a clash of two players who performed some notable upsets on their road to Round of 16. The Czech advanced after victories over the recent WTA 1000 champ from Montreal - Victoria Mboko winning 6-3, 6-2 and defeating Moyuka Uchijima 6-4, 6-2. The third round brought the clash with 10th seed and last year's semifinalist - Emma Navarro. The American won their last encounter on Wimbledon, stopping Krejcikova's title defence bid who was coming back to competition after being sidelined due to injuries. The Czech lost the opening set on Friday as well, but forced a decider. Despite trailing 0-3, 0-30 in the third set, the former world number two mounted a comeback to win it all by 4-6 6-4 6-4. Krejcikova is clearly returning to form after a back injury that sidelined her for the first six months of the 2025 season and shows no rust despite the lack of intense match practice.
Taylor Townsend continues her impressive run in New York. The American, ranked 139th in the WTA, stunned the tennis world by eliminating world No. 5 Mirra Andreeva 7-5, 6-2. That was possibly the most shocking upset of the round, considering the stunning form of Andreeva shown in first two rounds and her status of clear pre-match favorite. Townsend has neutralized the weapons of her younger opponent, allowing her to create just 3 breakpoints in compare to 12 made by herself and faced just 9 pressure points on serve, producing 24 of those on return. Townsend lives in the headlines from this tournament since second round, when she defeated 25th seed Jelena Ostapenko 7-5, 6-1, which ended in a heated exchange at the net. It's her second run into top 16 in Flushing Meadows after 6 years.
This will be the first meeting between Krejcikova and Townsend. The Czech won both her Grand Slam titles (Roland Garros 2021 and Wimbledon 2024) while ranked outside the Top 30, demonstrating her ability to elevate her game at crucial moments. Townsend has impressed with aggressive play - she hit 23 winners against Andreeva. The American also won 21 of 29 net points, showcasing her versatility and courage in attacking. This will be interesting to see if Krejcikova is on the road for another fairytale Grand Slam run, or Townsend will make her first ever Grand Slam quarterfinal.
