Third-seeded Marion Bartoli reached the semifinals of the $721,000 WTA hardcourt tournament on Friday as Ayumi Morita retired injured after dropping the first set of their quarterfinal.
France's Bartoli had won the first set 6-1 when Morita, the Japanese number one at 50 in the world, retired with a right ankle injury.
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.
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.
The night's glamor match pits Serena Williams against another former world number one, Maria Sharapova.
Sharapova is the second seed while Williams is unseeded as she works her way back up the rankings following an injury layoff of 11 months.
The winner of that match will face 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 semifinals at Wimbledon as a wildcard, but her dream run at the All England club was ended by eventual runner-up Sharapova.