World No. 3 Novak Djokovic and US Open champion Juan Martin del Potro kicked off their Australian Open preparations with easy first-round wins at the Kooyong Classic in Melbourne Wednesday. Del Potro cruised to a 6-3, 6-3 victory over Croatian Ivan Ljubicic, before Serbian Djokovic made light work of experienced German Tommy Haas 6-2, 6-3 at the eight-man invitational event. The 30-year-old Ljubicic, who took Roger Federer's place after the world No. 1 elected to skip his usual Australian Open warm-up, was upbeat about the loss despite spending most of the time between points frowning with his head bowed. “It wasn't all that bad actually. Probably the most disappointing thing is that I didn't feel bad at all and I still lost 6-3 6-3,” he said. Djokovic may face more of a work-out in the semifinal against Spanish world No. 9 Fernando Verdasco, who defeated Chilean Fernando Gonzalez 7-5, 6-1 in an occasionally farcical match later Wednesday. Jo-Wilfried Tsonga will take on Del Potro in the other semifinal after dismantling Robin Soderling 7-6, 6-1. Robredo progresses Top-seeded Tommy Robredo of Spain contended with a swirling wind to beat Germany's Simon Greul 7-6 (1), 7-6 (2) Wednesday and reach the quarterfinals of the Heineken Open. Robredo was playing his first match at the tournament after a first-round bye. Spaniards were the four top-seeded players in Auckland but Robredo's win was their only bright spot in the day session Wednesday. In a late match suspended by rain for more than an hour, Arnaud Clement of France beat second-seeded David Ferrer of Spain 7-5, 6-4. Third-seeded Juan Carlos Ferrero was forced to retire from his match against Swiss qualifier Michael Lammer with an ankle injury which may jeopardize his Australian Open campaign. Fourth-seeded Nicolas Almagro lost 6-0, 6-3 to 58th-ranked Marc Gicquel of France. The heavy serve of American John Isner carried him past seventh-seeded Juan Monaco of Argentina 5-7, 6-4, 6-3. In other matches, fifth-seeded Philipp Kohlschreiber, a former Auckland champion, beat Thomaz Bellucci of Brazil 6-4, 6-1 and sixth-seeded Jurgen Melzer of Austria beat French wild card entry Sebastien Grosjean 6-2, 6-7 (5), 7
