Britain's Bradley Wiggins held on to the overall lead of the Dauphine Libere after Frenchman Christophe Kern won stage five on Friday.
Wiggins, who claimed the yellow jersey following Wednesday's time trial, finished in sixth place.
He sustained the pace in the final 10km climb to Les Gets, with Belgian Juergen van den Broeck the only rival trying to unsettle the Team Sky leader.
Wiggins leads second-placed Australian Cadel Evans by one minute 11 seconds.
Defending champion Janez Brajkovic of Slovenia is 10 seconds further back.
"[Edvald] Boasson Hagen and [Geraint] Thomas did a fantastic job marshalling the pack and I used them as much as possible [in the final climb]," said Wiggins, who is using the race to prepare for next month's Tour de France.
Wiggins expects to face sterner tests in Saturday's sixth stage, which features the demanding climbs to the Col du Grand Cucheron and the Collet d'Allevard.
"We've always known it would be tough this weekend," he said. "I've trained very well in the last couple of months so I knew I had a good chance to win this race. I believe in my condition, where I'm at at the moment."
RadioShack's Jason McCartney broke away at the 95-kilometre mark to build a lead that reached 12 minutes 30 seconds, but the American rider was reeled in nine kilometres from the finish.
Three kilometres from the finish, Europcar rider Kern took charge of the race and fought off Dane Chris Anker Sorensen's challenge. Saxo Bank-Sungard rider Sorensen finished seven seconds behind.
Kern's team-mate Thomas Voeckler, the French champion, took third place, nine seconds off the pace.
Belgian Andy Cappelle pulled out of the race after crashing 21km from the finish in an incident that also involved Irishman Nicolas Roche.
Roche got back to his bike badly bruised but Cappelle could not continue after suffering a possible collarbone fracture and "head trauma".