SYDNEY (AFP) - Argentina's David Nalbandian scored a sweet victory over fierce Australian rival Lleyton Hewitt to power into the semi-finals of the Sydney ATP International on Thursday. The tournament fourth seed dominated with his groundstrokes from the back court as he parcelled up a 7-6 (7/3), 7-5 win over the former world number one in one hour and 48 minutes.Nalbandian, who still trails the Australian 3-2 in career meetings, next has a Friday semi-final with Frenchman Richard Gasquet. Top seed Novak Djokovic was frustrated by two rain delays, totalling almost two hours, before completing a 6-3, 6-4 win over Croatia's Mario Ancic in the night quarter-final. Djokovic will next play Jarkko Nieminen after the Finn received a walk-over into the semi-finals when his opponent, French third seed Jo-Wilfried Tsonga, pulled out with a lower back complaint, aggravated in Wednesday's second round.Unseeded Gasquet, a runner-up in last week's Brisbane International, was too strong for compatriot qualifier Jeremy Chardy, 6-2, 7-6 (7/4) in an earlier quarter-final."I think I should have won earlier, or easily in both sets," Nalbandian said. "I was a break up in both sets, but I couldn't make it in the first one, and even in the second one."It was a little complicated in both sets, but I won, so that's important."Nalbandian has had a long and at times bitter rivalry with Hewitt since the Australian's 2002 Wimbledon final triumph in straight sets.The pair exchanged sharp words in Hewitt's marathon five-set win over Nalbandian in the quarter-finals of the 2005 Australian Open. Hewitt's ranking has dropped to 74 since hip surgery last August, but he has been playing strongly in the Sydney tournament with victories over France's Julien Benneteau and Serbian Janko Tipsarevic. Hewitt was only playing his sixth match since undergoing the career-saving operation and will head into next week's Australian Open unseeded after reaching the 2005 final against Marat Safin. "I don't think I'm that far away from it," Hewitt said. "Especially because he's one of the best players in the world and probably capable of beating nearly anyone on any surface on any given day. "I had chances in both sets. It's probably just not having those tough matches against the best players that let me down today." Nalbandian was in control of the majority of his match with Hewitt. He broke the Australian twice in both sets, but double-faulted on break point as he served for the match at 5-4 in the second set after decisively winning the opening set tiebreaker. Gasquet has never beaten Nalbandian in six meetings and knows he is set for a tough assignment in the heat of an afternoon semi on Friday. "I never beaten Nalbandian and it will be a difficult game for me because he never misses, not so much," Gasquet said. "So it will be a big match for me. I won't be the favorite." But world number 25 Gasquet will be encouraged by his recent form heading into his second successive Australian tournament semi-final. "I played well in Brisbane and I'm feeling more confident because I've won more matches," he said. "I'm playing good. I've won in two sets all my matches in Sydney, so I will see tomorrow."