Chris Froome has revealed he has trained specifically to avoid fading and losing time to his rivals in the final week of the Tour de France.
The 31-year-old Team Sky rider won the Tour in 2013 and 2015 but on both occasions surrendered substantial amounts of time to nearest challenger Nairo Quintana in the closing mountain stages.
In 2013 he lost more than two and half minutes to the Colombian on stages 18, 19 and 20, while last year he shipped 1min 58sec on stages 19 and 20 and admitted afterwards that he had "died a thousand deaths" to retain the yellow jersey.
Given Quintana's ability to hold form and the fact that this year's final week features four tough stages in the Alps, Froome is determined not to leave himself hanging on once again.
Speaking to Sky Sports News HQ ahead of Saturday's opening stage in Normandy, he said: "I have made it a personal goal of mine to really try to focus on that third week and be better than I have been in the past.
"It's certainly going to be racing all the way up until stage 20 for us, with stage 17, 18, 19 and 20 being extremely hard days for the general classification riders."
Quintana finished runner-up to Froome in 2013 and 2015 and goes into this year's race as the bookmakers' second favourite following an excellent season in which he has won the Volta a Catalunya, Tour de Romandie and Route du Sud.
The 26-year-old also appears perfectly suited to the route, particularly the fact that the two time trials, on stages 13 and 18, are hilly rather than flat.
Alberto Contador and Richie Porte are the third and fourth favourites for victory, but Froome has no doubt who his main rival is.
He added: "I feel like the level of our competition has got that much stronger. We are up against tougher competition this time around. I feel like my rivals are in better shape than they have been in the past, and there are more of them.
"There are probably 10 guys who can potentially stand on that final podium in Paris.
"Right now, I would probably have to go with Nairo Quintana [as the main rival], given that he finished runner-up to me both times that I have won the Tour de France.
"He is more motivated than ever this year and it is a course that suits him incredibly well. It's a pure climbers' course. We have got a couple of time trials, but they are not flat; they are tough, they are hilly, which means that a climber will go well on them."
One of the keys to Froome's victory last year was the 1min 28sec he gained on Quintana on a wet and windy second stage, after the Colombian had been caught on the wrong side of a split in the peloton.
The opening two stages of this year's race take place on the Normandy coast, and with wind and rain forecast, Froome knows he has to stay vigilant.
He said: "A lot of the racing up here will depend on the weather on the day, the wind conditions. We could be in for a very nervous start. At least the first three days are going to be extremely nervous - fighting and jostling for position.
"With us we have got Ian Stannard, Luke Rowe and Vasil Kiryienka, who will hopefully keep us safe and out of trouble."
The Tour starts with a flat first stage from Mont-Saint-Michel to Saint-Marie-du-Mont and ends in Paris on Sunday, July 24.
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