Top seed Novak Djokovic overcame tenacious Czech Jan Hernych 7-5, 6-4 to reach the quarter-finals of the Marseille Open on Thursday.
Four Frenchmen, led by second seed Gilles Simon, also qualified for the last eight of the tournament.
Serb Djokovic broke early in his match but squandered the advantage before taking Hernych's serve again at the end of the first set.
Hernych, 29, produced another comeback in the second set while trailing 4-1, however world number three Djokovic made the most of his experience to prevail in 92 minutes.
"I was a little bit nervous and I made quite a lot of unforced errors, especially with my forehand. But the most important thing is that I won," Djokovic told reporters.
"I want to go as far as possible," the 21-year-old added.
Djokovic next meets German Mischa Zverev, who beat France's Arnaud Clement 6-4, 5-7, 6-2.
Simon found the going even harder in his 6-4 4-6 6-2 win over German Rainer Schuettler.
"When I came on court, my aim was to stay focused on my game," Frenchman Simon said. "All went well in the first set and I had the opportunity to take the lead early in the second but I lost my concentration and then I had to fight.
"I think I could have won in only two sets and it's a shame to spend so much time on court while we have to play every day," the world number eight added after his two-hour match.
Simon next faces compatriot Julien Benneteau, who booked his place in the quarter-finals with a 6-1, 2-6, 6-1 win over Swiss lucky loser George Bastl.
French fourth seed Jo-Wilfried Tsonga overpowered Italy's Simone Bolelli 6-3, 6-2 in an hour. He fired 10 aces and conceded only eight points on his serve.
"I was aggressive and took command of the game. I felt really well on court and that's why I tried some nice shots," Tsonga told reporters.
"I think I have reached a new level as I don't lose anymore against players ranked lower than me," added the 23-year-old, who meets Spain's Feliciano Lopez next.
In the evening match, Michael Llodra smashed