Second-seed Marion Bartoli overcame plucky Croatian Petra Martic 7-5 6-1 at the Open GDF Suez in Paris.
Bartoli only managed to keep 43 percent of her first serves in play in a tough first set, which involved seven breaks of serve.
Martic, 21, could not hold on against her French opponent though, as Bartoli improved her first serve percentage to 58 in the second set, in what ended up as a relatively easy match for the world number seven.
Bartoli will play veteran Italian Roberta Vinci in the last eight after the seventh seed survived a spirited comeback from American qualifier Bethanie Mattek-Sands to win 6-3 1-6 6-3.
It was better news for the other qualifier left in the draw as Mona Barthel of Germany beat wildcard Pauline Parmentier 6-3 6-0.
In the first match of the day, ninth-seed Angelique Kerber triumphed 6-3 4-6 6-3 over Romanian Monica Niculescu in a tight match.
The German will play top-seed Maria Sharapova in the third round.
Klara Zakopalova beat Tsvetana Pironkova 6-0 6-3 for the right to play sixth-seed Julia Goerges next and in the last match of the day, Belgian Yanina Wickmayer ended Christina McHale's tournament with a 6-2 7-5 victory.
Meanwhile, reigning champion Daniela Hantuchova booked her place in the Pattaya Open quarter-finals with victory over Urszula Radwanska.
Slovakian Hantuchova, seeded third for the WTA International event in Thailand, was a comfortable 6-3 6-2 victor over Pole Radwanska.
Hantuchova, who thrashed Sara Errani in the final of the hardcourt tournament last year, converted four of seven break-point chances in the easy win over the 85th-ranked Radwanska.
In the last eight, Hantuchova will face eighth seed Vania King after the American eased past Russian Alla Kudryavtseva 6-1 6-3.
King dominated the first set and won through the second despite an improved performance from Kudryavtseva.
Qualifier Hsieh Su-Wei, who upset China's Zheng Jie in the first round, progressed after a 7-5 6-0 win over Japanese veteran Kimiko Date-Krumm.
Taiwan's Hsieh has won eight WTA Tour doubles titles, and only lost 12 points in the second set against 41-year-old Date-Krumm.
She will face Sania Mirza in the quarter-finals after the Indian battled past Brit Anne Keothavong 6-4 7-5.