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.

Roberta Vinci of Italy and Yanina Wickmayer of Belgium also moved into the quarters along with Klara Zakopalova of the Czech Republic and Germans Mona Barthel and Angelique Kerber.

Bartoli, seeded second, won seven consecutive games to lead 4-0 in the second set despite seven double-aults.

"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 Bethanie 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.

In Friday's quarters, Kerber plays top-seeded Maria Sharapova, Wickmayer faces Barthel, Zakopalova meets sixth-seeded Julia Goerges of Germany and Vinci takes on Bartoli.