Unseeded Katie Boulter pulled off her fifth straight match win over a higher-ranked player as she upset Marta Kostyuk 5-7 6-2 6-2 in the San Diego Open final to claim her second title on the Hologic WTA Tour.
In her San Diego debut, the 27-year-old Boulter defeated Lesia Tsurenko, second seed Beatriz Haddad Maia, seventh seed Donna Vekic, third seed Emma Navarro, and lastly the sixth-seeded Kostyuk to win her first WTA 500 title and second overall, after she triumphed at the WTA 250-level grass-court tournament in Nottingham last season.