Roger Federer has pulled out of the ATP Finals less than one hour before his title match with Novak Djokovic, handing a third consecutive title to the top-ranked Serb.
The 17-time Grand Slam champion, who saved four match points in his semifinal win over Davis Cup teammate Stan Wawrinka, said back problems preventing him from playing.
Federer told fans at the O2 Arena: "Unfortunately I'm not match fit. I can't compete at this level with Novak in a finals like this." The Swiss added: "I hope you understand."
The 33-year-old Federer spent nearly three hours on court on Saturday evening
Federer, whose back problems ruined his 2013 season, is set to play in the Davis Cup final with Wawrinka next week against France.