Chris Froome is under no illusions that he faces a huge task to hold onto the Tour de France yellow jersey after assuming the lead following stage five.

As Fabio Aru impressively took the stage win, Froome was able to finish third and jump above Team Sky colleague Geraint Thomas at the top of La Planche des Belles Filles.

The past two riders to hold the leader's jersey after that particular summit – Bradley Wiggins and Vincenzo Nibali – have gone on to win the race, but with only five stages completed the defending champion knows that will not be easy to do in 2017.

"It's an amazing feeling to be back in yellow, but having said that I know race far, far from over, it's only just begun for me," said Froome. 

"I'm going to do everything to keep the yellow, but I have only got a small advantage and it's a long way to the finish. 

"I haven't raced much this year, I'm fresher at this part in the season and I hope in the third part of the Tour get better."

The only downside for Froome was allowing Aru to take 20 seconds out of his advantage and the Italian is someone the leader will be keeping a close eye on.

"Today went really well, the team did a great job, keeping me out of trouble and setting the pace on the final climb," he added.

"If anything we made a little bit of a mistake giving Aru that much space.

"He's showed already in the Dauphine that he's in great form and I think today just confirms that. Fabio is going to have to be one of the guys we really mark for the next couple of weeks."

For Aru it was his first stage win at the Tour and the Astana rider was delighted to have turned his attack into victory on Wednesday.

"I'm amazed. I attacked with three kilometres to go and gave it everything," he said.

"I wanted to see who would move because Team Sky was setting a fast pace. I wanted to see what they had.

"The final 300 metres were terrible, but then when I looked back with 200 metres to go, I knew I'd got it. 

"Winning in the tricolore jersey [Italian national team jersey] is a huge satisfaction. I had a very difficult spring but luckily, with a lot of hard work, things started to go my way."