Primoz Roglic took a giant leap towards a maiden Tour de France title when he extended his overall lead after the 17th stage on Wednesday. 

Colombian Miguel Angel Lopez prevailed at the end of the 170-km mountain rollercoaster from Grenoble, 15 seconds ahead of Roglic, who extended his advantage over fellow Slovenian Tadej Pogacar to 57 seconds, four days before the final parade in Paris. 

"Of course, I always want to win but I gained some time and I saw that others had problems. I knew I could gain time today and that's what we did," Roglic told reporters. 

For his part, Pogacar vowed to fight on. 

"It's not finished yet, tomorrow is a really hard stage and anything can happen. I can win, I can stay second – it's going to be a great fight," he said. 

Lopez moved up to third in the standings, 1:26 off the pace, ahead of another grueling mountain stage on Thursday, over 175km between Meribel and La Roche sur Foron. 

The stage started without defending champion Egan Bernal, who pulled out because of back pains, with his Ineos Grenadiers team saying he would focus on new goals this season. 

(With input from agencies)