SAN DIEGO (AP) — Marta Kostyuk of Ukraine, Daria Saville of Australia and Katie Boulter of England advanced to the quarterfinals of the Cymbiotika San Diego Open on Wednesday.
Kostyuk continues to build on the form that saw her reach her first major quarterfinal last month at the Australian Open. The sixth seed knocked off the last remaining wild card by beating 18-year-old Taylah Preston of Australia, 6-4, 6-3.
For Kostyuk, 21, it was almost like facing a mirror image of herself.
"I was playing her for the very first time. She's still very young. She reminds me a little bit of me," said Kostyuk, who finished with 25 winners to 17 unforced errors, including nine double-faults. "I knew I had to fight and grind. It was very close."
Preston, who notched her first tour-level main-draw singles win in the opening round against Magdalena Frech, impressed with her natural power and clean groundstrokes. She has jumped from No. 819 to No. 153 in a matter of one year, and will reach yet another career high when the updated WTA rankings are released on Monday.