George Hincapie has leaned into headwinds and rattled over cobblestones in Lance Armstrong's service for the past seven years, leading him through tight openings in a jostling, sprinting peloton and sacrificing his own ambitions.

On Sunday, it was Hincapie's turn to burst into the open. He won Stage 15 of the Tour de France after being out front in a breakaway nearly all day on the most demanding day of the race, a six-mountain marathon that Armstrong had eagerly anticipated since deciding this Tour, which ends next Sunday in Paris, would be his last.

Maintaining his overall lead at 2 minutes 46 seconds, Armstrong, who finished seventh in the stage, celebrated Hincapie's victory.

"He is my biggest guy, my biggest friend on the team," Armstrong said. "We've been riding together since we were 17. The guy is one of the best riders in cycling. Period. I'm so proud of him.

Hincapie is the only cyclist who has been with Armstrong for all of his Tour victories. "Unbelievable!" said Hincapie, a 32-year-old from Queens, N.Y., who got into cycling by following his father, a Colombian former amateur rider. "I'm in a state of shock right now."

Hincapie has won races in his own right, but was unaccustomed to the ritual that accompanies a Tour stage victory. At one point, fielding questions from reporters in two locations -- a van at the finish line and in a separate press room where questioners appear on a monitor -- Hincapie looked confused. "Where are those other people?" he asked.

The Tour has been good to Hincapie in the past, although in a different way. His wife, Melanie Simonneau, is a former podium hostess from Dijon, France, whom he met by asking an intermediary to slip her a note. The two proceeded to break the rule against riders socializing with the "podium girls," an infraction that resulted in Simonneau's firing. They subsequently married and have a baby daughter, Julia Paris.

With a Tour victory appearing more likely with each stage and a day off Monday, Armstrong focused on his friend.

"Every year, we have these dreamers who say they can win the Tour de France," Armstrong said. "Why can't George be in that position? He's a complete rider . . . one of the best riders in cycling today. This guy's a machine."

Hincapie was having none of that speculation.

"I'm having enough trying to deal with one thing right now," he said. "I just won the biggest race of my life. Let me think about this other stuff later. I've been working hard, and for Lance . . . to start saying stuff like that is pretty amazing."

Dirk Demol, the assistant director of Armstrong and Hincapie's Discovery Channel team, said the plan had been for Hincapie to go with any early breakaways so he could drop back and help Armstrong over the last couple of climbs. But Hincapie got the green light to make his own run when the group built an unbridgeable gap of more than 15 minutes after three of the six climbs.

With Armstrong in the overall lead, Hincapie didn't have to push the pace and stayed on other riders' wheels, conserving as much energy as he could on a hot day of climbing.

The breakaway group slowly shrank and, on the last part of the climb of Pla d'Adet, Phonak's Oscar Pereiro, who finished six seconds behind Hincapie, took off. Hincapie was the only rider who could follow.

The two plunged into a group of unruly Basque fans who pressed closer and closer as the climb went along, screaming, clapping the riders on the back and shaking flags, fists and other things in their faces. One spectator ran in front of an official's motorcycle that was cruising alongside the two riders and was knocked down, bringing the motorcycle with him.

Crowd control problems near the finish were exacerbated by the fact that so many fans had flocked to the mountain the night before that the advance crews who set up roadside barriers could only erect them on the last half-mile instead of the last two miles, as is customary.

"I told Pereiro we could work together once we got away, but I couldn't even go past him, there were so many people and no room to go," Hincapie said. "In that situation, I just stayed behind him. I knew if I was within the last kilometer with him, I could win in a sprint for sure."

Hincapie began his career as more of a pure speedster. When he is not riding support for Armstrong, he focuses on the European "classics," or long-established one-day races. He has honed his climbing skills in his offseason home in the hills of South Carolina, because, as he put it, "On this team, if you can't go uphill, you don't go to the Tour."

Wire services contributed to this report.

George Hincapie finds himself alone at the finish of the 15th stage. Hincapie, Lance Armstrong's teammate, beat Oscar Pereiro by six seconds. Overall leader Lance Armstrong climbs in the Pyrenees ahead of Italy's Ivan Basso, who remained 2:46 behind Armstrong but moved into 2nd place overall.