Former Tour de France winner Cadel Evans says the real battle for overall victory in the 2013 race starts on the road to the ski resort at Ax-Trois-Domaines in the Pyrenees.

Speaking after a tough seventh stage won by Slovakian Peter Sagan the Australian suggested he was coming into form at the right time in the three-week race.

BMC's Evans praised the "aggressive" riding of Sagan's Cannondale team on Friday which strung out the peloton on the road to Albi.

"It was pretty much one line the whole way and one line means it's on," the 2007 winner said.

"No worries (though) I like the hard conditions that's what I need, actually, to bring myself up.

"The real race for GC starts tomorrow so we'll see what we can do there."

Saturday has the first of two consecutive stages in the Pyrenees.

Evans, 36, said the eighth stage would deliver the first real selection and show who was capable of winning in Paris.

But he suggested the big time gaps would occur in the Alps in the final week.

Many breakaway specialists hadn't even tried to escape up the road in the opening stages "because they know how hard the second and third weeks really will be".

There was no change among the leaders or those most fancied for overall honours on Friday.

Of the Australians former leader Simon Gerrans remains third, five seconds off the pace, Richie Porte is eighth, Michael Rogers 12th and Evans 22nd.

Daryl Impey finished 12th in the sprint into Albi meaning Orica-GreenEdge will hold the yellow jersey for four days in only their second Tour.

But he's likely to relinquish it on Saturday.

Race favourite Chris Froome had a "comfortable day" despite Friday's pace and Sky said he, along with Tasmanian teammate Porte, were in strong positions ahead of the first mountain-top finish.

"It will definitely be a fight on the climb tomorrow," Froome said on the team's website.

"This is what we've trained for and we're looking forward to putting it to good use now."

Porte tweeted that he was "looking forward to getting into the mountains tomorrow".

Sky hopes Porte can help Froome win the Tour and also finish on the podium himself.

The 28-year-old won the Paris-Nice race in March.