Second-seeded Tomas Berdych advanced to the quarterfinals of the ABN Amro World Tennis Tournament on Thursday when Marcos Baghdatis retired with a leg injury in the fourth game.

Also, third-seeded Juan Martin del Potro fired nine aces to advance with a 6-4, 7-5 win over Karol Beck of Slovakia.

Baghdatis was injured in the opening games as Berdych raced to a 3-0 lead.

A trainer strapped Baghdatis' calf and he returned to the court, but the Cypriot still hobbled and gave up a couple of points later.

In other second-round matches, fifth-seeded Richard Gasquet beat Alex Bogomolov Jr. 6-3, 6-2 and Andreas Seppi of Italy overcame Philipp Kohlschreiber of Germany 6-4, 6-2. Seventh-seeded Viktor Troicki beat Jesse Huta Gulang of the Netherlands 7-6 (2), 6-3 in just over two hours.

Top-seeded Roger Federer returns to action on Friday in a quarterfinal against Jarkko Nieminen of Finland.

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