It's Ahn to the San Jose quarterfinals after big upset

Stanford graduate Kristie Ahn, playing in Berkeley two weeks ago,
stunned third-seeded Elise Mertens to reach the quarterfinals of a
WTA tournament for the second time. Photo by Paul Bauman

   Kristie Ahn almost cracked the top 100 in early 2018.
   It could happen this year.
   Ahn, a qualifier from Englewood Cliffs, N.J., stunned third-seeded Elise Mertens of Belgium 6-3, 6-3 today to reach the quarterfinals of the Mubadala Silicon Valley Classic at San Jose State.
   The 20th-ranked Mertens, a semifinalist in last year's inaugural tournament in San Jose, committed 10 double faults to none for the 178th-ranked Ahn.
   Ahn, a 27-year-old graduate of nearby Stanford from Englewood Cliffs, N.J., earned her first victory over a top-20 player and advanced to the quarters of a WTA tournament for the second time. She will soar to at least No. 137, 32 spots below her career high, on Monday.
   Ahn, only 5-foot-5 (1.65 meters), shocked 2017 French Open champion Jelena Ostapenko in the first round on clay in Bogota in April and earned her first Wimbledon main-draw berth last month.
   In her last tournament, Ahn became so frustrated in a semifinal loss to Madison Brengle in the $60,000 Berkeley Tennis Club Challenge that she flung her racket into the crowd. No one was hurt.

   Ahn is scheduled to play fifth-seeded Donna Vekic of Croatia for the first time on Friday not before 4 p.m. Vekic, ranked No. 25, beat former world No. 1 Victoria Azarenka, who won the 2010 Bank of the West Classic at Stanford, 6-4, 6-3.
   In Friday night's featured match at 7, fourth-seeded Amanda Anisimova, 17, of Aventura, Fla., will play unseeded Zheng Saisai of China.

Donna Vekic of Croatia celebrates during her 6-4, 6-3
victory over former world No. 1 Victoria Azarenka.
Photo by Mal Taam

   Anisimova, ranked No. 23 after reaching the French Open semifinals in June, overpowered Brengle, the Berkeley champion, 6-2, 6-2 in 54 minutes. Zheng, ranked No. 55, whipped eighth-seeded Danielle Collins, an American who reached the San Jose semifinals last year, 6-2, 6-0 in 61 minutes.
   Anisimova, who won her first professional title at 15 in the 2017 Sacramento Challenger, overwhelmed Zheng 6-1, 6-1 in the second round at Hiroshima last September en route to her first WTA final, in which she lost to crafty veteran Hsieh Su-Wei of Taiwan.
   In Friday's other quarterfinals, second-seeded Aryna Sabalenka of Belarus will meet sixth-seeded Carla Suarez Navarro of Spain at noon, followed by top-seeded Elina Svitolina of Ukraine against seventh seed and 2018 runner-up Maria Sakkari of Greece.
   The 5-foot-11 (1.82-meter) Sabalenka, 21, is 2-0 against the 5-foot-4 (1.62-meter) Suarez Navarro, 30, including a 6-1, 6-4 victory in the New Haven final last August.
   Suarez Navarro won the doubles title in the 2014 Bank of the West Classic with countrywoman Garbine Muguruza, who last week withdrew from the Silicon Valley Classic for the second consecutive year with an injury.
   Svitolina, a semifinalist in the 2015 Bank of the West Classic in her only other San Francisco Bay Area appearance, defeated Sakkari 6-3, 6-7 (1), 6-2 in the third round at Wimbledon last month in their only career meeting. Svitolina, 24, went on to become the first Ukrainian woman to reach the semifinals at the All England Lawn Tennis Club, her best Grand Slam result.
   Here are the San Jose singles and doubles draws and Friday's schedule.