Montpellier - Richard Gasquet broke Nikolay Davydenko three times and didn't concede a single break chance in winning 6-3, 6-4 to reach the Open Sud de France quarter-finals on Wednesday.
Neither are fixtures in the world top 10 but the fourth-seeded Frenchman was wary.
"He's not the No 3 he was a few years ago, but he can still dazzle sometimes, and you can easily find yourself a break down against him," Gasquet said. "So it was important to hold my serve."
Davydenko led 40-15 on serve in the 10th game of the second set, but Gasquet took a forehand early to pass Davydenko, who next hit an unforced error and watched as Gasquet dispatched a volley to get to his first match point.
Davydenko saved that with his fifth ace. Gasquet wasted his next chance when a hurried backhand pass hit the net, then double-faulted on his third match point and watched as Davydenko saved another with a clipped forehand pass.
Gasquet, who reached the fourth round at the Australian Open, sealed victory on his fifth match point after a long baseline rally ended with the Russian slicing a forehand well wide.
"I'm glad he missed that as it was becoming harder to get my first serve in," said Gasquet, who has slipped from a ranking of seventh in 2007 to 16th. "I've recovered from Australia now and am starting to sleep properly, so everything's fine."
Guillaume Rufin of France also advanced after a 7-6 (7/5), 6-3 win over fifth-seeded Feliciano Lopez of Spain.
Rufin hit 16 aces compared to 13 for Lopez, who lost his serve twice in the second set after the big servers swapped a break each in the first.
Results from the third day of the ATP event on Wednesday (x denotes seeding):
Guillaume Rufin (FRA) bt Feliciano Lopez (ESP x5) 7-6 (7/5), 6-3
Richard Gasquet (FRA x4) bt Nikolay Davydenko (RUS) 6-3, 6-4
Philipp Kohlschreiber (GER x7) bt Edouard Roger-Vasselin (FRA) 6-4, 7-5