Goffin replaces Monfils at ATP Finals

Frenchman Gael Monfils has withdrawn from the ATP World Tour Finals with a rib injury, leaving Novak Djokovic to play alternate David Goffin in his final group match.

World No.6 Monfils, a debutant at the tournament after an impressive year in which he reached the US Open semi-final, could not make the last four in London after losses to Milos Raonic and Dominic Thiem in his opening two matches.

"Definitely I can't play for tomorrow because I feel worse and worse with my ribs," he told reporters.

"I couldn't practise."

Monfils sustained the injury in Stockholm in October and was told that it would be a six-week recovery period.

"I tried to make it, but I couldn't," he said.

Defending champion Djokovic has already booked a semi-final spot, but will be desperate to beat Belgium's Goffin to grab another 200 points in the race to beat Andy Murray to the end-of-year world number one ranking.

Goffin finished the year ranked 11th.