Day 7: Djokovic v Nadal

Sue Barker presents live coverage of the ATP Tour semi-finals from the O2 Arena in London.

At this stage of last year's tournament, crowd favourite and six-time winner Roger Federer reached the final thanks to victory over Swiss compatriot Stanislas Wawrinka. However, he had to pull out of the final with Novak Djokovic due to a back injury, handing the Serbian a third straight victory in the season-ending tournament.

Commentary by Andrew Castle and Tim Henman.