Tennis great Roger Federer has personally appeared on court to apologise after withdrawing from the ATP World Tour Finals in London due to injury.

Thirty minutes before he was due to play against world number one Novak Djokovic on Sunday night, Federer withdrew with a back injury and personally apologised to the crowd.

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“I’m sorry I’m here in a track suit and not in a match outfit. Unfortunately I’m not match fit to play the match tonight,” Federer told the crowd.

“I hope you understand I wanted to come out personally and excuse myself for not playing.”

The 33-year-old said it would be too risky at his age to participate in the match injured.

“I tried everything I could last night and today – painkillers, rest – until the very end but I can’t compete at this level with Novak,” Federer said.

“In a final like this and at my age it would be too risky. I hope you understand.”

Federer injured his back before defeating Stan Wawrinka in the semifinals on Saturday, and said he tried everything to recover in time for the final.

Djokovic automatically won the title but played Andy Murray in an exhibition match, winning 8-5.

According to a report by The Guardian, Murray was playing the ‘Mario Kart’ video game when he got the call to play.