ROGER FEDERER says he'll be fit to play in the Davis Cup final, which starts on Friday.

The world No.2 pulled out of the final of the ATP World Tour Finals in London against Novak Djokovic with a back injury after his semi-final win over Stan Wawrinka,

Federer and Wawrinka are due to play in Lille as the Swiss try to beat France and claim a first Davis Cup title.