Roger Federer has made an impressive start in his bid for a seventh ATP Tour Finals title with a crushing 6-3 6-1 win over the Serb Janko Tipsarevic.
Federer's victory in a match lasting just 68 minutes took him to 40 match wins at the prestigious season-ending event, breaking the previous record of 39 held by Ivan Lendl.
The towering Argentine Juan Martin Del Potro lost to the in-form Spaniard David Ferrer, the Paris Masters champion winning 6-3 3-6 6-4 in front of a packed audience at the 17,000 O2 Arena alongside the River Thames.
Fourth seed Ferrer, whose victory was the 73rd of a season that has delivered a career-best seven titles, will face Federer on Thursday trying to gain a first victory at the 14th attempt.
On the first day the world tennis number one Novak Djokovic and US Open champion Andy Murray both scored wins, Murray withstanding an early onslaught to beat Tomas Berdych in three sets while Novak Djokovic beat Jo-Wilfried Tsonga 7-6 6-3 to move top of group A.