Italy's Sara Errani ended the French resistance at the Pan Pacific Open, rallying to defeat ninth seed Marion Bartoli 3-6, 6-2, 6-2 to reach the last eight of the WTA premier five event on Wednesday.
The sixth seed finally overcame Bartoli after two hours and 22 minutes, clinching victory with a crunching forehand her opponent could only dump into the net.
"I'm a bit tired but I have lots of motivation to keep winning," said Errani, who has captured titles in Acapulco, Barcelona, Budapest and Palermo this year.
"It's been an amazing year but I still have to qualify for the (season-ending) Championships."
Errani set up a quarter-final against Russia's Nadia Petrova, the 17th seed battling to a 7-6, 6-7, 6-4 victory over Croatia's Petra Martic.
Last year's US Open champion Samantha Stosur, seeded eighth, also booked her place in the last eight with a 6-4, 7-5 win over Slovakia's Dominika Cibulkova.
Nine of the world's top 10 women are competing at the event, with US Open champion Serena Williams the only absentee among the WTA's elite.
Photograph: Clive Brunskill/Getty Images