Great Britain’s Katie Boulter stunned sixth-seeded Ukrainian Marta Kostyuk on Sunday, coming back for a 5-7, 6-2, 6-2 victory in the final of the San Diego Open. Boulter grabbed her first title at the WTA 500 level. Ranked 49th in the world, she is the lowest-ranked player to snag a WTA 500 title since Liudmila Samsonova did so at the 2021 German Open. Samsonova was ranked 106th at the time. All five victories Boulter recorded at the San Diego Open came against top-50 opponents. Kostyuk led 1-0 in both the second and third sets, but it was all Boulter from there. The latter saved seven of 11 break points and overcame 13 double faults. Kostyuk finished with just one ace. ATX Open No. 8 seed Yue Yuan of China upset sixth-seeded countrywoman Xiyu Wang, recording a 6-4, 7-6 (4) sweep in the final in Austin, Texas.