ROTTERDAM, Netherlands, Feb. 21 (UPI) --
Defending champion Radek Stepanek
advanced past the first round Wednesday at the ABN AMRO World Tennis Tournament in Rotterdam, Netherlands.
Novak Djokovic and David Ferrer, seeded fifth and sixth in the event, also moved into the quarterfinals.
Stepanek, the eighth seed this year, won his sixth straight match at this tournament with a 6-2, 7-5, decision over fellow Czech Jan Hernych. Djokovic outlasted Andrei Pavel, 6-7 (8-10), 6-1, 6-3.
Ferrer prevailed over Kristof Vliegen, 6-4, 6-2.
Gilles Simon, who won last week's tour stop in Marseille, was forced to retire during the second set of his match against Philipp Kohlschreiber. Simon, suffering from a hamstring pull, was eliminated, 6-3, 3-1.
© 2007 United Press International, Inc. All Rights Reserved. Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI's prior written consent.