Two-time Australian Open champion Victoria Azarenka has turned back the clock to stun world No.3 Jessica Pegula in straight sets and reach her third Melbourne Park semi-final.

Azarenka, the 2012 and 2013 Open champion, defeated close friend Pegula 6-4 6-1 to reach the final four in Melbourne for the first time since sealing back-to-back triumphs 10 years ago.

The No.24 seed, who is also a three-time US Open finalist, teed up a tantalising clash with Wimbledon champion Elena Rybakina, who earlier easily accounted for Jelena Ostapenko 6-2 6-4.

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“It hurts to beat her (Pegula) because I always want her to do well,” Azarenka said.

“She’s been playing amazing, very consistent and I knew from the first point I had to bring it.

“I just wanted to try to stay there, take opportunities because she was going to take everything if I don’t try to win myself. I’m very proud that I executed my game plan really well.

“It’s so amazing to be in the semi-final of another grand slam.”

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Plenty has changed for Azarenka in the 10 years since her last semi-final in Melbourne – she is now 33 and a mother, but her aggressive baseline play was a reminder of her past triumphs.

The upset means all of the top four seeds – Iga Swiatek, Ons Jabeur, Pegula and Caroline Garcia – have failed to reach the semi-finals in Melbourne, while world No.5 Aryna Sabalenka is the only top-20 player left.

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Pegula, 28, hadn’t dropped a set in Melbourne before facing Azarenka and had appeared primed to kick on and reach a semi-final at a slam for the first time.

But Azarenka worked over the American while Pegula struggled to get her serve going as she made a third straight quarter-final exit at Melbourne Park.

Azarenka raced away to a 3-0 lead in the first set but struggled to close it out, requiring five set points across three games to claim it as Pegula found a foothold in the match.

But the Belarusian needed just 33 minutes to cruise through the second set and seal an ultimately comfortable victory.