(CNN) -- Chris Froome conquered Mont Ventoux at the Tour de France to extend his overall lead with a week remaining in cycling's most prestigious race. 

In a fascinating battle Sunday, Team Sky's Froome caught and then passed Nairo Quintana during the steep 13-mile climb to give him a four-minute cushion over his nearest rivals. 

A spent Froome had to be given oxygen when the 15th stage -- the longest of this year's Tour at 150 miles -- ended but he'll get a chance to recover during Monday's day off. 

On Bastille Day French hopes were dashed, as Sylvain Chavanel lost his lead to Movistar's Quintana before the Colombian faded and Froome charged. 

"I thought he'd be less strong than he was," Quintana told the Tour's website. 

Froome has now won both stages with summit finishes. 

"I didn't expect to win," Britain's Froome said after nearly six hours of racing. "I wanted to get more of a buffer on the general classification but I didn't think I could go for the win. 

"Quintana is a very strong climber and I wasn't expecting him to go from as far as he did but hats off to him. He did a great ride and he showed how strong he is." 

Despite the gruelling end to the stage, Froome and Quintana -- one to watch for the future -- had time for a quick chat. 

"In the last (1.2 miles) he was fading a little and I still had a little bit left," said Froome. "I was just trying to say, 'Man, come on just a little bit more, we're almost there.' But he was slipping behind. 
What country is the leader from?
 Britain's Froome