Sky leader Richie Porte has said he believes that Friday’s summit finish of the Tour de France could suit him well and that he is looking forward to battling it out with race leader Vincenzo Nibali (Astana) plus the other overall contenders in several hour’s time.

The Hors Categorie climb of Chamrousse is the most difficult the riders have faced thus far and will take the peloton to the finish 1730 metres above sea level. The final climb is 18.2 kilometres long and averages 7.3 percent in gradient.

“It is a hors cat climb. Obviously it is the first big, big climb in the race and I think it is going to be decisive,” the Australian said. “I think we will see some bigger gaps forming. I am actually looking forward to it after those last two transfer stages that we had.”

Porte is two minutes 23 seconds behind Nibali in the overall standings and is the closest challenger to the Italian. The time trial on the penultimate day could suit him well, but he knows that he has to narrow the gap to stand a chance.

He said that he hoped the ascent will play to his strengths. “To be honest with you, the longer climbs are I think more my territory,” he said. “I think the race is really going to start now.”

He came into the race as a support rider for defending champion Chris Froome. He was listed as the number two competitor and, once Froome was forced to withdraw due to injury, he stepped up to the head of the team.

Porte said that he has a mix of emotions at being so prominent as the Tour heads into the next crucial phase.

“Being a young fellow from Australia and watching Cadel years back finishing second, I remember what a big feat it was at the time. It is nice to have that opportunity to lead the team and to make the most of it.”

The race to Chamrousse will tell a lot about his prospects for the overall. If he can take time out of Nibali – or even match him – it will keep his yellow jersey hopes on course. If the Italian succeeds in opening up a larger gap, his race may be more about the battle for second.

That said, Porte, Nibali and the other riders will be aware that everyone in the peloton can have a bad day. Nibali has been in winning form since he took stage two; many are wondering if he can continue at the same level for the rest of the race.

He has said that he wants to open up more time, and so the stage to Chamrousse should end up being a very dramatic one.