PARIS -- Marion Bartoli of France defeated Petra Martic of Croatia 7-5, 6-1 Thursday to reach the Open GDF Suez quarterfinals while Americans Bethanie Mattek-Sands and Christina McHale failed to make it out of the second round.
Bartoli, seeded second, won seven consecutive games to lead 4-0 in the second set despite seven double-faults.
"My serve cost me in the first set," she said. "Either I was making double-faults or I was serving too softly."
Vinci beat qualifier Mattek-Sands 6-3, 1-6, 6-3. The seventh-seeded Italian broke twice in the final set, clinching victory when Mattek-Sands netted a backhand.
Mattek-Sands struggled with her serve in the first set, making four double-faults and landing only 45 percent of her first serves. But the American jumped ahead 5-0 in the next set to even the match when Vinci sent a forehand wide.
Mattek-Sands finished the match despite a lower back injury. She was in pain at 3-2 in the decider, sobbing during the changeover and calling a therapist to massage her left hip and thigh.
Wickmayer ousted McHale 6-2, 7-5. The 19-year-old American saved three match points at 5-4, but Wickmayer converted her fourth match point when the youngest player in the top 50 sent a backhand wide.
Barthel defeated French wild card Pauline Parmentier 6-3, 6-0. The German qualifier, who won the Hobart International last month in Australia, converted her second match point with a backhand crosscourt winner.
Zakopalova advanced to her first quarterfinal since the Korea Open in September, cruising past Tsvetana Pironkova 6-0, 6-3.
Kerber, a U.S. Open semifinalist, edged Monica Niculescu of Romania 6-3, 4-6, 6-3.