Elena Dementieva was the first player to book her quarter-final place at the French Open, beating fifth seed Lindsay Davenport in straight sets.
The ninth seed raced to a 4-0 lead in the first set, which she won 6-1 and then took the second 6-4.
The 22-year-old Russian will now play either third seed Amelie Mauresmo or Bulgaria's Maggie Maleeva.
Davenport was targetting the only Grand Slam title she is yet to win, but was severely hampered by a knee injury.
"I tweaked my knee in the second set and it was really sore," she said.
"I decided to keep the points short, it probably would have been better to stop.
"I don't think it's a fractured cartilage, just a bruise but I would be extremely bummed if I had to spend more time away. It's been a great year for me so far, so hopefully this is just a blip."