Roger Federer concedes he needed some luck to get through his opening match at the ATP World Tour Finals but says he's feeling fit and is happy with the level of tennis he's playing.
The Swiss maestro started his bid for a record sixth World Tour Finals title with a three sets victory over France's Jo-Wilfried Tsonga.
The 30-year-old, down to fourth in the world rankings, will finish the year without a grand slam title for the first time since 2002, but is continuing his history of impressive end of season form.
Federer says Tsonga gave him a real scare in London.
