MELBOURNE, Australia -- Victoria Azarenka's 18-match winning streak at the Australian Open ended in an upset 6-1, 5-7, 6-0 quarterfinal loss to Agnieszka Radwanska on Wednesday, continuing the flow of stars tumbling out of the season's first major.
Fifth-seeded Radwanska ended her own streak of three consecutive quarterfinal defeats at the Australian Open with a stunning display of versatile shot-making that shocked and confused the big-hitting Azarenka.
The result means both defending champions were out in the quarterfinals -- Novak Djokovic lost in five sets to Stan Wawrinka the previous night.
Azarenka's defeat followed the fourth-round exits of top-ranked Serena Williams and Maria Sharapova and leaves 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.
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 didn't fall into big-swinging rallies against the second-seeded Azarenka, either, continually mixing it up and saving the power for when she needed it.
"She was aggressive. She was making everything. She was guessing right," Azarenka said. "I was just playing a little bit too predictably.
"In the second set I managed to fight back. Third set, the first game was important. I let it go, like easily let it go. From there just couldn't get back to it. It was tough."
Radwanska was also safe on her own serve, dropping just two games in the two-hour match while breaking Azarenka six times. She hadn't beaten Azarenka in their last seven matches, and had only won three of their previous 13.
"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 of her first run to the semis of a major on hard courts. She reached the final at Wimbledon in 2012, becoming the first player from Poland to reach a major final in the Open Era, and the semifinals last year.
"I just had to play my best tennis, even better and play aggressive and go for every shot I could," Radwanska said of her win over the two-time defending champion.
Azarenka went down in a flurry of unforced errors, making 47 in three sets as she tried to push Radwanska around.
She seemed to have momentum at the end of the second set, when she leveled after breaking in the last game. But she didn't carry it through, pushing a forehand fractionally too wide on the first point and unsuccessfully challenging the out call.
It was a sign of things to come. She won only 14 points in the third set, and was broken three times.
Azarenka was booed late in the match, when she smashed a ball into the back of the court after another frustrating error. She screamed loudly after losing big points to the incredibly consistent Radwanska, punched her thigh and her racket and even slapped the court. 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."