MEGEVE, France — Chris Froome won a mountain time trial to extend his overall lead at the Tour de France in the 18th stage on Thursday.

Taking his second stage win of this year's Tour, Froome finished 21 seconds ahead of Dutch rider Tom Dumoulin over the 17-kilometre (10.5-mile) route from Sallanches to the Megeve ski resort — which featured majestic views of Mont Blanc.

It was the Tour's first mountain time trial since the 2004 race against the clock up l'Alpe d'Huez. Besides the flat opening four kilometres (2.5 miles) and a short descent at the finish, it was entirely uphill.

Two more Alpine stages remain before Sunday's mostly ceremonial finish on the Champs-Elysees.