Jack Sock claims he has "nothing to lose" in the upcoming ATP World Tour Finals given that he is not expected to do much at the O2.

I've got nothing to lose - Sock

I've got nothing to lose - Sock

The 25-year-old American was the final player to book his place in the end-of-season showpiece tournament in London courtesy of Sunday's Paris Masters final success against Filip Krajinovic.

Sock will subsequently be thrown in at the deep end as he his first game on Sunday is against Roger Federer, who has enjoyed a renaissance in 2017 by taking his career Grand Slam tally to 19 courtesy of wins in the Australia Open and at Wimbledon.

Sock has never defeated the Swiss star so far in his career, but he is going into the game knowing there is little pressure of expectation on his shoulders.

He told Standard Sport: "Roger and I are friends off the court but, on it, it's a battle.

"I've not beaten him but I can take a lot of experience from those encounters and, after the biggest title of my career, I'm confident.

"As the last guy into the tournament, I think I can play freely. I've got nothing to lose."