Roger Federer has begun the defence of his ATP World Tour Finals title in the best possible fashion by coming through in three sets against Jo-Wilfried Tsonga.
The Swiss legend has now won 13 straight matches on tour after his afternoon's topsy-turvy victory at the O2 in London.
Federer, currently the world number four, began strongly, breaking Tsonga twice in the opening set to move ahead 6-2.
The Frenchman however rallied in the second, producing some explosive play to mimic Federer's efforts in the first to level the match.
Both men held serve in the decider but Tsonga faltered in the tenth at 4-5, handing Federer the crucial break to clinch the match.
The other two players in group B, French Open champion Rafael Nadal and Mardy Fish, meet in the evening's game at around 8pm.
