World number one Rafael Nadal qualified for the semi-finals of the ATP World Tour Finals on Friday with a 7-6 6-1 defeat of Czech Tomas Berdych.
Nadal needed to be at his best to subdue Berdych in a high-quality repeat of this year's Wimbledon final and finish top of Group A with a maximum three victories.
Runners-up spot in the group will be decided later when Serbia's Novak Djokovic takes on American Andy Roddick.
Nadal, who needed 70 minutes to get the better of Berdych in a superbly entertaining opening set at a packed O2 Arena, joins Roger Federer and home favourite Andy Murray in the semi-finals.
The Spaniard is bidding to win the elite year-end tournament for the first time having reached the semi-finals in 2006 and 2007. Last year, when the O2 hosted the event for the first time, he failed to win a match.
