Froome in trouble but still extends Tour lead

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.

Race leader yellow jersey holder Team Sky rider Froome of Britain climbs the Alpe d'Huez mountain during the 172.5km eighteenth stage of the centenary Tour de France cycling race from Gap to l'Alpe d'Huez

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

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.

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.

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

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 kilometre to go. Italian Moser Moreno was third.

(Editing By Alison Wildey)