MELBOURNE, Australia -- Roger Federer rekindled his dominance over Andy Murray in Grand Slam matches and advanced to his 11th consecutive Australian Open semifinal with a 6-3, 6-4, 6-7 (6), 6-3 win Wednesday.
Both Nadal and Federer certainly had nervous moments.
Murray, who saved two match points in the third-set tiebreaker, has an 11-10 edge over Federer in head-to-head matches and won their last match in five sets in the Australian Open semifinals last year, but Federer has won four of five matches in majors.
The Wimbledon champion got angry after a ruling while dropping serve late in the third set when he indicated that he thought the ball had bounced twice before Federer kept it in play. It sparked his resurgence, breaking Federer when the 17-time major winner was serving for the match, and then pushing it to a fourh when he won the last six points in the tiebreaker.
After spending three months off the circuit following minor back surgery, Murray appeared to be in discomfort at times in the match, clutching at his lower back.
''I was proud of the way I fought,'' Murray said.
After Federer won the opening game of the fourth set, the two played a 10-deuce game in which Murray saved six break points before Murray leveled. But Federer finally broke Murray in the eighth game then held serve to win the match in 3 hours, 20 minutes.
''I'm probably one of the guys who misses more break-point opportunities than other guys so I'm kind of used to it,'' Federer said. ''You stay positive -- give yourself a chance.''
Nadal avoided the top player exodus that claimed two-time defending women's champion Azarenka in the preceding match on center court.
Azarenka won't have a semifinal date. No. 5-ranked Radwanska stopped Azarenka's 18-match winning run at Melbourne Park with a 6-1, 5-7, 6-0 win earlier in the day.
That means both defending champions went out in the quarterfinals -- Novak Djokovic lost to Stanislas Wawrinka on Tuesday, ending his bid for a fourth consecutive men's title. Azarenka had been aiming for three in a row and other women's title contenders Serena Williams and Maria Sharapova didn't even make it as far as the quarterfinals.
Nadal won on his fourth match point on Dimitrov's serve in 3 hours, 37 minutes, a long time after his celebration following a second-set tiebreaker that more resembled a victory dance. He stayed in a squat position after his winning cross-court shot and then pumped his chest out three times.
There were more muted celebrations after a tiebreaker in the third set, with Nadal acknowledging Dimitrov let him off the hook with a wide forehand on set point.
''It's a tough moment mentally for an opponent,'' Nadal said. ''If that forehand from him goes in and he wins the third, I'm going to be fighting.''
Nadal fended off three set points in the third set, including two in the tiebreaker, and won on his first set point.
He went up 2-0 in the fourth when he hit a passing backhand down the line on break point with Dimitrov standing at the net. At the end, Dimitrov appeared to wipe tears from his eyes with a towel as he walked off Rod Laver Arena.
Dimitrov was still emotional during his post-match news conference, tearing up while discussing the forehand that got away.
''Obviously I got to put that in the past,'' he said. I'm sure I could have done something different. But in a match everything comes down to a split of a second ... whether in or out.''
Earlier, he said: ''I'm a bit shattered. I came out expecting nothing less than to win.''
Azarenka's defeat left 2011 French Open champion Li Na as the only major winner remaining in the women's draw. Radwanska next plays No. 20 Dominika Cibulkova, who won the last eight games in a one-hour, 6-3, 6-0 quarterfinal rout of No. 11-seeded Simona Halep earlier Wednesday.
Li, a two-time finalist in Australia, will play 19-year-old Canadian Eugenie Bouchard in the other semifinal.
Radwanska played drop shots and slices from the baseline, forcing Azarenka to come forward and then lobbing or passing her. She hit touch volleys with calm precision, and instinctively anticipated Azarenka's shots.
''She was aggressive. She was making everything. She was guessing right,'' Azarenka said. ''I was just playing a little bit too predictably.
Radwanska was also safe on her own serve, dropping just two games while breaking Azarenka six times. She hadn't beaten Azarenka in their last seven matches.
''I said to myself one day I have to have one step forward and do the semifinal, and I'm so, so happy that I did it finally,'' Radwanska said.
Azarenka was booed late in the match when she smashed a ball into the back of the court after another one of her 47 unforced errors. She screamed loudly after losing big points to the incredibly consistent Radwanska, punched her thigh and her racket and even slapped the court with her hand. Nothing worked to change her fortunes.
''I'm not happy with what I did today, but on the court I felt like I could have played a lot better,'' Azarenka said. ''I can't take away what she's done today. She played amazing.''