Fourth seed Juan Martin Del Potro fought back from a set down to beat Frenchman Richard Gasquet in the first match of Group B at the ATP World Tour Finals here.
The Argentine big server took two hours and 23 minutes Monday to defeat the eighth seed 6-7 (4), 6-3, 7-5, reports Xinhua.
The win was crucial for Del Potro, who faces defending champion Novak Djokovic and Roger Federer in the other two group matches.
Del Potro came to London following two victories last month in Tokyo and Basel. He also beat Rafael Nadal to make the final of the Shanghai Masters.
Gasquet, competing for the second time after 2007, was ranked ninth but qualified thanks to the withdrawal of third-ranked Andy Murray.
