Christophe Riblon of France crosses the finish line to win the eighteenth stage of the Tour de France cycling race over 172.5 kilometers starting in Gap and finishing in Alpe-d'Huez, France, Thursday July 18, 2013. (AP Photo/Peter Dejong)

Christophe Riblon of France crosses the finish line to win the eighteenth stage of the Tour de France cycling race over 172.5 kilometers starting in Gap and finishing in Alpe-d’Huez, France, Thursday July 18, 2013. (AP Photo/Peter Dejong)

L’ALPE D’HUEZ, France (Reuters) – Britain’s Chris Froome again left rival Alberto Contador in his wake despite cracking on Thursday’s 18th stage of the Tour de France that was won by Frenchman Christophe Riblon.

Froome, in a group of three chasing the leading riders, was clearly in trouble in the final five kilometers as he climbed l’Alpe d’Huez for the second time on the 172.5-km stage.

Christopher Froome of Britain, wearing the overall leader's yellow jersey, and Nairo Alexander Quintana of Colombia, wearing the best young rider's white jersey, pass through Alpe-d'Huez during the eighteenth stage of the Tour de France cycling race over 172.5 kilometers starting in Gap and finishing in Alpe-d'Huez, France, Thursday July 18, 2013. (AP Photo/Peter Dejong)

Christopher Froome of Britain, wearing the overall leader’s yellow jersey, and Nairo Alexander Quintana of Colombia, wearing the best young rider’s white jersey, pass through Alpe-d’Huez during the eighteenth stage of the Tour de France cycling race over 172.5 kilometers starting in Gap and finishing in Alpe-d’Huez, France, Thursday July 18, 2013. (AP Photo/Peter Dejong)

He sent team mate Richie Porte back to the team car to fetch some food and drink and the Australian nursed Froome to the line.

Christopher Froome of Britain, wearing the overall leader's yellow jersey, says thanks to teammate Richie Porte of Australia, right, as they cross the finish line of the eighteenth stage of the Tour de France cycling race over 172.5 kilometers starting in Gap and finishing in Alpe-d'Huez, France, Thursday July 18, 2013. (AP Photo/Peter Dejong)

Christopher Froome of Britain, wearing the overall leader’s yellow jersey, says thanks to teammate Richie Porte of Australia, right, as they cross the finish line of the eighteenth stage of the Tour de France cycling race over 172.5 kilometers starting in Gap and finishing in Alpe-d’Huez, France, Thursday July 18, 2013. (AP Photo/Peter Dejong)

Luckily for Froome, his main rival, Contador, had already paid the price for earlier attacks on the mountainous stage and the Spaniard finished almost a minute behind the yellow jersey.

The former Tour champion is now five minutes, 11 seconds behind Froome in the overall standings, with three stages left to race.

The pack with Christopher Froome of Britain, wearing the overall leader's yellow jersey, and Jakob Fuglsang of Denmark, far left in light blue, climbs Alpe-d'Huez pass during the eighteenth stage of the Tour de France cycling race over 172.5 kilometers starting in Gap and finishing in Alpe-d'Huez, France, Thursday July 18, 2013. (AP Photo/Laurent Cipriani)

The pack with Christopher Froome of Britain, wearing the overall leader’s yellow jersey, and Jakob Fuglsang of Denmark, far left in light blue, climbs Alpe-d’Huez pass during the eighteenth stage of the Tour de France cycling race over 172.5 kilometers starting in Gap and finishing in Alpe-d’Huez, France, Thursday July 18, 2013. (AP Photo/Laurent Cipriani)

Riblon’s stage victory was France’s first of this year’s Tour, celebrating its 100th edition.

The pack with Richie Porte of Australia, Christopher Froome of Britaina, wearing the overall leader's yellow jersey, Nairo Alexander Quintana of Colombia, wearing the best young rider's white jersey, and Pierre Rolland of France, from right, climb Alpe-d'Huez pass during the eighteenth stage of the Tour de France cycling race over172.5 kilometers starting in Gap and finishing in Alpe-d'Huez, France, Thursday July 18, 2013. (AP Photo/Laurent Cipriani)

The pack with Richie Porte of Australia, Christopher Froome of Britaina, wearing the overall leader’s yellow jersey, Nairo Alexander Quintana of Colombia, wearing the best young rider’s white jersey, and Pierre Rolland of France, from right, climb Alpe-d’Huez pass during the eighteenth stage of the Tour de France cycling race over172.5 kilometers starting in Gap and finishing in Alpe-d’Huez, France, Thursday July 18, 2013. (AP Photo/Laurent Cipriani)

The AG2R rider produced a determined ride up the final stages of l’Alpe d’Huez and passed leader Tejay van Garderen of the U.S. with just over one kilometer to go. Italian Moser Moreno was third.

The pack with Christopher Froome of Britain, wearing the overall leader's yellow jersey, climbs Alpe-d'Huez pass during the eighteenth stage of the Tour de France cycling race over 172.5 kilometers starting in Gap and finishing in Alpe-d'Huez, France, Thursday July 18, 2013. (AP Photo/Christophe Ena)

The pack with Christopher Froome of Britain, wearing the overall leader’s yellow jersey, climbs Alpe-d’Huez pass during the eighteenth stage of the Tour de France cycling race over 172.5 kilometers starting in Gap and finishing in Alpe-d’Huez, France, Thursday July 18, 2013. (AP Photo/Christophe Ena)

(Editing By Alison Wildey)