MELBOURNE - Roger Federer and Rafael Nadal pencilled in the next chapter of their great rivalry when they reached the Australian Open semi-finals Tuesday, as Kim Clijsters gave Caroline Wozniacki a day to forget.

Federer was majestic in his defeat of Juan Martin del Potro but Nadal had a stiffer challenge in his night match against Tomas Berdych, as they set up their 10th grand slam meeting. The results gave Federer a chance to avenge his bitter final defeat of 2009, when Nadal's five-set win left the Swiss weeping freely in front of his idol, Rod Laver. The Spaniard leads their slam meetings 7-2, and is 17-9 overall.

Nadal had a fight on his hands when he lost the first set to Berdych but the redoubtable second seed came through 6-7 (5/7), 7-6 (8/6), 6-4, 6-3 over 4hr 16min on Rod Laver Arena. He described the 2009 final as "unforgettable" after he survived the longest match in Australian Open history in the semi-finals, against Fernando Verdasco, and then went the distance again versus Federer.

"Seriously, that final is one of the memories that will always be in my mind," he said.

Earlier Federer, a four-time winner at Melbourne Park, was at his serene best in the afternoon heat as he made light of an expected tough test by del Potro, his conqueror in the 2009 US Open final.

The 16-time grand slam winner, now 30, and playing his 1,000th tour-level match, barely gave the 6ft 6in (198cm) Argentine a look-in and he took it 6-4, 6-3, 6-2 after 1hr 59min of glorious tennis. Federer started like a rocket and broke at the first opportunity, taking the first set in 43 minutes. In the second set, he fought off four break points in a pivotal game nine to go 2-0 up, marking it with a trademark guttural roar.

Del Potro has returned to 11th in the rankings after serious injury but his head dropped in the third set as Federer closed it out with his thunderous inside-out forehands and classic, one-handed backhand. The victory put a broad smile on the face of the Swiss, who is aiming to become only the second man to win the Australian Open five times or more after Roy Emerson -- who was watching from the stands -- in the 1960s.

"I'm very happy," Federer said. "I thought it was a great match. It was tough with the sun and shade creeping across the court but I thought we did well. I thought it was a high-quality match." Federer and Nadal will resume their rivalry on Thursday, while top seed Novak Djokovic plays David Ferrer and world number four Andy Murray takes on Kei Nishikori in Wednesday's quarter-finals.

Meanwhile women's defending champion Clijsters ousted top seed Wozniacki and ended her controversial reign as world number one with a straight-sets win in the quarter-finals. Clijsters held off a determined fight-back from the 21-year-old Dane to win 6-3, 7-6 (7/4) in 1hr 45min and set up a semi-final against third seed Victoria Azarenka, who beat Poland's Agnieszka Radwanska.

By failing to reach the last four, Wozniacki is guaranteed to lose her number one ranking to Azarenka, Petra Kvitova or Maria Sharapova when the new standings are released next Monday.

Wozniacki has occupied the top spot since October 11, 2010, apart from one week last February, but she has faced constant questions over her right to be considered the best women's player, because she has never won a major title.

But the defiant Dane, who lost her only grand slam final to Clijsters at the 2009 US Open, backed herself to bounce back by the end of the year. "You know, to be honest, I don't really think about it," a defiant Wozniacki said.

"I have been there for a long time already. I finished number one two years in a row. We are just in January. In the end of the year you see who has played the best, most consistently all year round. I will get it back eventually, so I'm not worried." Former champion Sharapova and Ekaterina Makarova will contest an all-Russian quarter-final on Wednesday, while Wimbledon title-holder Kvitova plays Sara Errani of Italy.