MELBOURNE, Australia — Victoria Azarenka ousted defending champion Kim Clijsters 6-4, 1-6, 6-3 today to advance to the Australian Open women's final.Azarenka will play in her first Grand Slam final Saturday in her 25th major. She will take on the winner of today's later semifinal between Maria Sharapova and Petra Kvitova.Azarenka, Sharapova or Kvitova will take over the No. 1 ranking vacated by Caroline Wozniacki after Wozniacki's loss to 11th-seeded Clijsters in the quarterfinals at Melbourne Park. Meanwhile, on the men's side, Novak Djokovic overcame leg and breathing struggles to secure a "Big 4" semifinal lineup.The top-ranked player and defending champion held off No. 5 David Ferrer in a second-set tiebreaker Wednesday and raced through the third set for a 6-4, 7-6 (7-4), 6-1 quarterfinal win, setting up a semi with fourth-ranked Andy Murray, his opponent in last year's final.Second-ranked Rafael Nadal and No. 3 Roger Federer have a semifinal showdown today, their 10th clash at a major. This is the 14th time since the Open era began in 1968 that the top four seeded players reached the semifinals in a major.For 10 days nearly everyone at Melbourne Park had said the top four were playing on a higher level than the rest of the men. But then Djokovic looked to be in trouble."No, I don't have any physical issues," Djokovic said. "It's just I found it very difficult after a long time to breathe because I felt the whole day my nose was closed a little bit. I just wasn't able to get enough oxygen."The win ensured that the top four men reached the semifinals for the third time in four Grand Slams. Murray beat Kei Nishikori 6-3, 6-3, 6-1.At times, Djokovic, 24, looked exhausted. At times he looked sore. "At this stage of the tournament, when you're playing somebody like David, somebody that has great shots from both sides from the baseline, makes you always play over five to 10 shots in the rally, your physical strength and endurance comes into question," Djokovic said. "Actually, I'm not concerned about that at all. I'm really fit."