SAINT-AMAND-MONTROND, France — Mark Cavendish won the 13th stage of the Tour de France in a sprint finish Friday and Chris Froome lost a sizeable chunk of his overall lead after being caught out by Alberto Contador.

Flat stages are normally relatively free of incident, but the 173-kilometer (107.5-mile) trek from Tours to Saint-Amand-Montrond showed that even Froome's formidable Sky team can be vulnerable.

With about a third of the stage gone, the main pack was split into three and Alejandro Valverde dropped way out of overall contention after stopping to repair a puncture and losing a huge amount of time.

Valverde was second overnight but that spot was overtaken by Dutchman Bauke Mollema, while the two-time former champion Contador improved to third. They both gained more than one minute on Froome.