Serena Williams shrugged off her unseeded status and delivered a dominating 6-1, 6-3 victory over second-seeded Maria Sharapova to reach the semi-finals of the WTA Stanford tournament.
Williams, a 13-time Grand Slam champion who is unseeded thanks to a ranking slump caused by a lengthy injury layoff, showed Friday she's still a contender as she overpowered Sharapova, who struggled throughout with her serve.
"I had a good start," Williams said. "You can't go in against the fifth-ranked player with your mind everywhere. You have to be serious. It's a great win for the hardcourt season."
Williams was playing just her third tournament since she won Wimbledon in 2010, having been sidelined for 11 months by a series of health problems including a cut foot that required surgery and blood clots in her lungs.
"I'm a better player this month than I was last month," Williams said. "I've put in a lot of work and I hope it continues to pay off."
Currently ranked 169th, Williams defeated Sharapova for the sixth straight time and improved to 7-2 overall against her.
"I consider anybody I play to be an intense rivalry but we do have a good thing going," Williams said. "It's exciting and it's good for tennis."
Sharapova, fresh off a runner-up finish at Wimbledon, hasn't beaten Williams since the 2004 WTA Championships.
The Russian didn't give herself any chance to turn the tables in this one.
"It certainly wasn't my night," Sharapova admitted. "She was serving and hitting so well and I was extremely late in my reactions. I felt sluggish. It was a bad day but it's also a reminder that I need to step up.
"When I had chances to change things around I couldn't do it," Sharapova added. "Her biggest strength is her power and you don't see so much of that in the top 10. It really makes her dangerous."
Williams next faces big-hitting German Sabine Lisicki, a 7-6 (7/4), 2-6, 6-2 winner over fifth-seeded Agnieszka Radwanska of Poland.
Lisicki made it to the semi-finals at Wimbledon as a wildcard, but her dream run at the All England Club was ended by eventual runner-up Sharapova.
"I'm looking forward to the match," Lisicki said. "I love competing in the big matches. I have nothing to lose."
Third-seeded Marion Bartoli reached the semi-finals as Ayumi Morita retired with a right ankle injury after dropping the first set of their quarter-final 6-1.
It was a disappointing exit for Morita, who had beaten former world number one Ana Ivanovic of Serbia in the first round and survived two match points as she rallied to beat Polish qualifier Urszula Radwanska in the second round on Thursday.
France's Bartoli next faces eighth-seeded Slovakian Dominika Cibulkova, who breezed past New Zealand qualifier Marina Erakovic 6-1, 6-1.
Erakovic had stunned top seed and defending champion Victoria Azarenka on Thursday, but couldn't find an answer for Cibulkova, who needed little more than an hour to advance.