Roger Federer says he is already looking forward to his second match of the ATP World Tour Finals in London after opening his campaign with a straight-sets win over debutant Jack Sock.

Federer, who is aiming to triumph at the season-ending event for the seventh time, came into the tournament at The O2 in sparkling form after his success at the Swiss Indoors.

The Swiss legend also tasted success at the Australian Open and Wimbledon this year whilst further titles at the Indian Wells Masters, Miami Open, Halle Open and Shanghai Masters were added to his collection.

His 15th appearance in the World Tour Finals has got off to a perfect start with the world number two producing a good display to defeat American Sock 6-4 7-6.

The 36-year-old from Basel served five aces, won 90 per cent of his first serve points, made a total of 28 winners and made just 20 unforced errors to get off to a winning start in the Boris Becker group.

Federer knows a victory against Alexander Zverev, who defeated Maric Cilic in three sets, on Tuesday will put him in a strong position to qualify and the 19-time Grand Slam champion is excited about his next outing.

He told Sky Sports after the match: “I’m happy to have gone through. It feels wonderful to be back – I love playing at The O2.

I can’t wait for my next match on Tuesday.” Federer, who is 1.40 favourite to win the tournament, is quoted the shortest price at 1.25 to win the Pete Sampras Group whilst Zverev is a 3.80 chance.