Federer off to winning start

Roger Federer started his ATP World Tour Finals campaign with a 6-4, 7-6 (7/4) win over American debutant Jack Sock at The O2 Arena in London last night.

Federer, who was making his 15th appearance at the season-ending tournament for the world's top-eight players, will next meet big-serving Croat Marin Cilic tomorrow. Germany's Alexander Zverev completes their group.

In the other group, Dominic Thiem takes on Grigor Dimitrov tonight, with Rafael Nadal meeting David Goffin later. - WIRE SERVICES

Roger Federer