GERARDMER LA MAUSELAINE, FRANCE - JULY 12: Alberto Contador of Spain and Tinkoff-Saxo (L) puts in a late attack to gain seconds on current race leader Vincenzo Nibali (R) of Italy and the Astana Pro Team on stage eight of the 2014 Tour de France, a 161km stage between Tomblaine and Gerardmer La Mauselaine, on July 12, 2014 in Gerardmer La Mauselaine, France. (Photo by Bryn Lennon/Getty Images)

Mulhouse, France – Alberto Contador vowed to go on the attack as Frenchman Tony Gallopin looks to defend the Tour de France yellow jersey on Bastille Day.

Two-time winner Contador has 2min 34sec to make up on Vincenzo Nibali after suffering badly on Wednesday's cobbled stage.

Nibali was in yellow until Sunday when his Astana team allowed a breakaway group enough of a gap to let the race lead pass to Gallopin.

But the 26-year-old Frenchman will have his work cut out keeping the jersey on the first tough mountain stage of the race.

Someone who will be relishing the 161.5km run from Mulhouse to La Planche des Belles Filles is Contador and, legs permitting, he's planning fireworks.

“I need to see how things turn out and whether or not I need to adopt a strategy of conservation or one of attack,” said the Spanish Tinkoff-Saxo team leader.

“If my legs feel good, I'll go on the attack. It depends how well I recover and how I feel.

“Once it's clear how strong everyone is, that's when you see what happens.

“It feels like we've already covered a lot of ground but we cannot switch off and let opportunities go.

“Nibali and the others in front of me in the standings are great riders and day by day I need to climb back up.”

Contador slipped to ninth in the standings after three of Sunday's breakaway group jumped into the top 10 thanks to the five minutes they gained on those above them.

Nibali held the yellow jersey for a week but said his team's forces were spent defending it and they couldn't chase any longer.

“(Sunday) the team worked hard all day. Gallopin took the yellow jersey and there's no need to lose one's head,” said the Italian.

“We managed to get through the day pretty well. Of the overall contenders (Pierre) Rolland closed in a bit.

“We knew it would be a day for an escape but no-one helped us.”

He added: “Everyone worked hard, even the 'passisti' (those less suited to the mountains), and they're spent.”

The final 5.9km first category ascent to Monday's finish will ensure there's a serious shake up in the overall standings, according to Geraint Thomas.

The Welshman will be working for new Sky team leader Richie Porte Ä who replaced Chris Froome when he crashed out of the Tour on Wednesday.

“It's up and down all day and I think the GC will really get sorted out. There will be a lot of tired bodies and some big attacks on the last climb,” he said.

Porte dropped to fifth Sunday as Gallopin and Portuguese Tiago Machado moved into the top three.

But he is likely to find himself in the top three by the end of Monday's stage.

At least he's one of those Contador is wary of.

“Right now Nibali, (Aljeandro) Valverde and Porte are showing good form. The ideal would be to put time into them,” he said.

As well as the brutal finish, there are seven categorised climbs, including four first category ones on what should be a tough day in the saddle.

Gallopin knows he needs an incredible performance to maintain his 1:34 lead over Nibali, but he's hoping the yellow jersey effect, not to mention that of donning the famous shirt on his country's national day, will inspire him.

“It's incredible. It will be a very proud moment to wear the yellow jersey on the national day. I would never have imagined it,” he said.

“I think I'll really enjoy it (Monday). It won't be an easy day, the guys (going for overall victory) will try to do battle.

“I have just 1:30 to Nibali. I will do my best.” – Sapa-AFP