Four-time Australian Open champion Federer advanced to his ninth straight semifinal at Melbourne Park with a 6-4, 6-3, 6-2 quarter-final win Tuesday over Juan Martin del Potro, the man who beat him for the U.S. Open title in 2009.
Federer's 1,000th match was similar to most in his career — no-nonsense, dominating from the start and hitting some incredible shots.
"It's a lot of matches and a lot tennis," said Federer, a record 16-time Grand Slam champion. "Either I have been around for a long time or I'm extremely fit. You decide which way you want to describe it. But I'm happy."
In an often tempestuous night match at Rod Laver Arena, Nadal advanced with a tough 6-7 (5), 7-6 (6), 6-4, 6-3 win over Tomas Berdych.
"Happy with how I finished match physically, I was able to keep running with high intensity," Nadal said.
Federer and Nadal — they were ranked 1-2 for many years — have been on opposite halves of the draw since the 2005 French Open. That was the last time the pair met in a Grand Slam semifinal, won that year by Nadal in four sets.
"The ranking is important, but we are talking about a player who has won 16 Grand Slams, and I've won 10," Nadal said.
"We have played a lot of matches together, many in very important moments for our careers. So the matches against him are always special, even if we are (ranked) 20 against 25."
Defending women's champion Kim Clijsters, still dealing with a left ankle injury, advanced to an Australian Open semifinal against third-seeded Victoria Azarenka by beating No. 1 Caroline Wozniacki 6-3, 7-6 (4) Tuesday. Clijsters' victory ensured that Wozniacki would lose the top ranking she has held for most of the last 15 months.
Azarenka beat No. 8 Agnieszka Radwanska 6-7 (0), 6-0, 6-2. Azarenka is one of three women who could finish at No. 1 in Melbourne — Maria Sharapova and Petra Kvitova are the others.
In the late match, Nadal saved four set points in the first set, including one on an amazing crosscourt passing shot on the 29th point of a rally. But Berdych held firm to win the ensuing tiebreaker.
During the tiebreaker, a Berdych shot landed out, and Nadal returned it, then challenged. Chair umpire Carlos Bernardes wouldn't allow the challenge because Nadal hadn't immediately stopped play, but Nadal responded by saying he didn't challenge immediately because he thought the linesman had called it out.
The replay showed the ball was out.
"Carlos, I'll tell you something, you never get one right, not one correct overrule," Nadal said in Spanish. "You're not here as a spectator. You know that ball was out."
Nadal was still debating the issue at his post-match news conference.
Later in the match, Bernardes had a brief discussion with Berdych when the Czech player complained about an apparent "flat" ball. And in the fourth set, Nadal chastised the chair umpire again for allowing a challenge by Berdych, feeling the Czech player waited too long before asking for a review.
In the opening game of the fourth set, Nadal hit consecutive down-the-line forehands to break Berdych's service and the Spaniard was on his way to clinch the match in 4 hours, 16 minutes.
Nadal said he changed his strategy after losing the first set.
"I started moving a little bit inside the court after I went 20 metres behind the baseline, just trying to find solution," Nadal said. "At the end of the match I finished it returning fantastic."
Berdych said his performance "was only good, which means that is not enough with Rafa."
Federer's career can be enhanced even more if he wins the title this year at Melbourne Park. With a 232-34 record in Grand Slam singles matches, he can overtake Jimmy Connors' mark of 233 wins if he collects the title here.
Del Potro, who has recovered from the right wrist injury that sidelined him for most of 2010, played well in flashes. But Federer was at another level, hitting lobs, drop shots, crosscourt winners and generally negating Del Potro's big forehand.
"We have played some big matches against each other, so just knowing how well he's been playing as of late, I was just hoping that I would get off a good start," Federer said. "I was able to mix it up well and control the ball, and right away sort of felt confident."
The end of the match came in a most fitting way, one of Federer's backhand winners.
Before that, Federer saved his fourth break point at 5-3 in the second set after a long rally. He let out a loud yell, unusual for a player not prone to big shows of emotion.
"That's why I didn't celebrate when I won the set, just to make it up," Federer said, smiling. "I really knew how important that game was for me."
The quarter-finals on the other side of the men's draw are Wednesday — Andy Murray plays Kei Nishikori of Japan and top-seeded Novak Djokovic takes on David Ferrer.
In the remaining women's quarter-finals Wednesday, Sharapova plays Ekaterina Makarova, who beat five-time champion Serena Williams in the fourth round, and No. 2 Kvitova takes on unseeded Sara Errani of Italy.
Clijsters has needed treatment on her ankle since Sunday, when she injured it and had to save four match points in her fourth-round win over French Open champion Li Na, a rematch of the 2011 final.
"Instead of really focusing on the match, you're focusing on trying to get the ankle as good as possible," Clijsters said of her preparation. "Laying on the couch, every 20 minutes ice, 20 minutes off, 20 minutes ice, 20 minutes off. Leg elevated. Lymphatic drainage, all that stuff."
Wozniacki, 21, needed to reach the semifinals to retain the top ranking.
"I will get it back eventually, so I'm not worried," she said. Critics "talk to me like I'm finishing my career and I only have one year left and time is running out. The fact is I still have quite a few good years in front of me."
In junior boy's play, Vancouver's Filip Peliwo won his second-round match, defeating Jack Schipanski of Australia 6-2, 6-4. Peliwo then teamed up with Serbian Pedja Krstin to beat Borna Coric of Croatia and Pietro Licciardi of Italy, 2-6, 6-2, 10-6 tiebreak in doubles.
Montreal's Eugenie Bouchard, seeded second among junior girls, downed Iva Mekovec of Croatia 6-3, 3-6, 6-3. But Carol Zhao of Richmond Hill, Ont., lost to No. 9 Anna Schmiedlova of Slovakia 4-6, 7-5, 6-2.
Bouchard and Zhao won in doubles, stopping Miyu Kato and Risa Ozaki of Japan 6-2, 6-4.