Italy's Fabio Aru discovered another gear and pulled away from three-time Tour de France champion Chris Froome to win the fifth stage on Wednesday in Vittel, France.
While Aru was victorious in the first mountain climb of the race, Froome rode well enough up the steep ascent to the La Planche des Belles Filles ski station to take the overall race lead and the yellow jersey from Sky teammate Geraint Thomas of Great Britain.
Froome, who leads the overall race by 12 seconds over Thomas, won his first Tour de France stage at the La Planche des Belles Filles in 2012. Aru, who won his first career Tour de France stage on Wednesday, resides 14 seconds behind the leader.
Wearing his country's colors, Aru benefited from a burst of speed to bolster his lead on Wednesday with more than 1 1/2 miles left to go in the stage.
"It's extraordinary for me to win this stage," said the 26-year-old Aru, who represents the Astana team.
Irishman Dan Martin, who is on Quickstep, secured a second-place finish on Wednesday to move into fourth place overall, 25 seconds behind the leader. Froome finished third on Wednesday.
"I remember the first time I was in yellow in 2013," Froome said. "It was a bit of an overwhelming experience to be honest, but I think I've spent enough days in yellow now to get used to that.
"I know what I'm up against. This is going to be the hardest-fought battle in terms of the general classification and I know my rivals are right up there."
Also on Wednesday, rider Mark Cavendish praised the race's organizers for disqualifying world champion Peter Sagan after the latter delivered an elbow that ended his participation in the event.
"It takes a lot of courage to eliminate the world champion from the Tour de France," said Cavendish, who has won 30 Tour stages during his career.
Cavendish was attempting to slide in between Sagan and the barriers on Tuesday when he ran into the Slovakian's elbow, causing the Brit to crash and take down two other riders.