The Australian has been tipped by team boss Marc Madiot as a future winner of one of the big three Tours.

But McGee believes his career will be defined in the five arduous hours he expects to spend in the saddle for stage 10 from Grenoble to Courchevel.

"The Courchevel climb will decide what I can do as a rider for the rest of my career," he told BBC Sport.

"If I'm in the main group of climbers when we go over the mountain-top finish, or at least within a shout of them, I can home in.

"And, having survived that brutal hill at the finish, that will enable me to go for the general classification.

"If I can't do it then, I'd question whether I have it in me at all."

McGee has already matched some of the peloton's best climbers, most notably with his eighth place overall at last year's Giro d'Italia.

It's a horrid beast that robs you of everything you've got and I don't know why we do it do ourselves
Brad McGee on the terror of the Tour's climbs And he added: "I've improved so much, most notably with that Giro run a year ago.

"This year I was with the main guys on the main climbs in the Dauphine Libere and it felt pretty good. I saw the odd climbing spot we're going to tackle in the Tour which is always pretty good for the confidence."

The Sydney-born 29-year-old struggled to transfer his Giro form into last year's Tour - but because of the rigours of a big tour, it is notoriously hard to peak for both.

This time, though, his focus has been solely on the Tour de France and even his Francaise des Jeux team's orders have changed to help his cause.

"This is the first year I'm really trying to break my way into