Elena Dementieva moved into the last eight at the French Open for only the second time with victory over fellow Russian Vera Zvonarena.

The seventh seed, who made the final in 2004, won 6-4 1-6 6-2.

Zvonareva made a total of 41 unforced errors, repeatedly smacking her racquet into the ground in frustration as the final set slipped away.

Dementieva will face the winner of top seed Maria Sharapova's clash with Dinara Safina in the quarter-finals.