Wimbledon champion Garbine Muguruza swept into the semi-finals of the WTA hardcourt tournament at Stanford on Friday with a 6-1, 6-3 win over Ana Konjuh.
Spanish top seed Muguruza needed just 62 minutes to get past the fifth-seeded Croatian, breaking Konjuh's serve five times and never trailing in their first career meeting.
"I think today I was very accurate," said Muguruza, the world number four who is playing her first tournament since beating American Venus Williams in the final at Wimbledon to claim a second career Grand Slam title to go with her 2016 French Open crown.
"Ana is such a powerful player and super-young," Muguruza said. "I knew I had to be concentrated. I'm super happy that I'm through to the semi-finals, and I'm pretty happy with the match."
Muguruza next faces either third-seeded American Madison Keys or seventh-seeded Lesia Tsurenko of Ukraine.
Second-seeded Czech Petra Kvitova's quarter-final clash with eighth-seeded American CiCi Bellis highlighted the night session, with the winner to take on either sixth-seeded American CoCo Vandeweghe or fourth-seeded Russian Anastasia Pavlyuchenkova.
The last time the top eight seeds reached the quarter-finals of a WTA tournament was in Philadelphia in 2004.
Muguruza, Kvitova, Pavlyuchenkova and Tsurenko are all seeking a second title of the year.
© 2017 AFP