Sagan won a sprint after the Slovakian launched an instinctive attack with 12 kilometres to go alongside Tinkoff team-mate Maciej Bodnar of Poland and Team Sky’s Froome and Geraint Thomas.

The quartet quickly pulled away and then managed to hang on until finish with Sagan comfortably overcoming Froome in a sprint for the line.

The winning time was 3 hours 26min 23sec, while the peloton finished six seconds later.

"It was crazy," said Sagan.

"Froome and Geraint came with us and I said, 'we are too strong, they are never going to catch us'.

"So we pulled hard and it happened

"There was a crazy wind and I was not planning to go in the break with the yellow jersey and Geraint and Bodnar.

"You cannot plan that - it just happens."

Froome received a six-second bonus for his second-place finish on the 162.5km stage, stretching his lead over fellow Briton Adam Yates of Orica-BikeExchange at the top of the general classification to 28 seconds.

Ireland’s Dan Martin of Etixx-Quick-Step remains third but is now 31 seconds adrift, while Colombia’s Nairo Quintana of Movistar is still fourth but is now 35 seconds off the pace.

With cross winds threatening to split the race throughout, the day turned out to be one of the toughest of the race so far.

The peloton was almost all back together with 15km remaining, however, Sagan then broke clear with Bodnar.

Spotting a chance to gain time on his rivals for the general classification, Froome followed with compatriot Thomas and the foursome soon opened up a lead that stretched out to a maximum of 26 seconds.

This was cut to six seconds by the finish, but the stage was still a success for Froome.

"Any opportunity I can see I'm going to take it," said the two-time Tour winner. 

"This is bike racing at its best.

"I feel like I'm enjoying it, I'm not feeling I'm being forced into this because of pressure."

Sagan collected 67 points in the green jersey classification; 50 for winning the stage and 17 in an intermediate sprint.

He now leads Britain’s Mark Cavendish by 90 points and appears certain to claim a fifth consecutive title.

Race organisers have announced that the planned finish on top of Mont Ventoux has been cancelled due to high winds in Provence.

The 12th stage will now finish 6km down the mountain at Chalet Reynard.

The second stage of the Tour of Poland, another International Cycling Union (UCI) WorldTour race, saw Colombia’s Fernando Gaviria sprint to victory at the end of a 128km course from Tarnowskie Góry to Katowice.

Gaviria finished ahead of Italy’s Elia Viviani and Australia's Caleb Ewan in a time of 3:19:30.

It ensured his second UCI WorldTour win of the season and he will now wear as overall race leader’s jersey for the 240km third stage in Zawiercie.