Paris: Juan Martin del Potro set up a French Open quarter-final against Roger Federer by finishing off a 7-6 (6), 1-6, 6-3, 7-5 victory over Tomas Berdych on Monday in a match stopped the night before because of darkness after three sets.
The No. 9-seeded del Potro broke No. 7 Berdych at love in the final game.
Del Potro is 2-11 against Federer, but one of the victories came in the 2009 U.S. Open final, when the Argentine won his only Grand Slam title.