American Jessica Pegula stunned powerful fifth seed Maria Sakkari to fly into her second straight Australian Open quarter-final on Sunday.

The 21st seed stormed through a first-set tiebreaker and kept her foot to the gas in overpowering the Greek 7-6 (7/0), 6-3 on Margaret Court Arena.

She will play either world number one and title favourite Ashleigh Barty or Naomi Osaka’s conqueror Amanda Anisimova for a place on the semi-finals.

“That was definitely my best match of the year,” said Pegula, who has been relaxing in Melbourne by playing Blackjack at a local casino.

“I thought I returned really well, I wanted to put pressure on her serve and I felt I did that. I was trying to be patient and play as smart as I could.”

The 27-year-old Pegula, whose billionaire father Terry owns the Buffalo Bills NFL club, also made the last eight in 2021, when she lost to fellow American Jennifer Brady.

Right-hander Sakkari, who made the semis at both the US Open and French Open last year, had a 2-0 win-loss record over Pegula and had not dropped a set at Melbourne Park.

But she found the going tough in searing heat.

They traded blows throughout the first set until the tiebreak when Pegula found another gear with her flat and fast groundstrokes helping her race through it without dropping a point.

She earned a break in the second set to move 4-1 and held on to take the win when Sakkari slapped a backhand wide.

Krejcikova crushes injured Azarenka

Barbora Krejcikova blew away former two-time champion Victoria Azarenka in the last 16 of the Australian Open.

French Open champion Krejcikova easily overcame Azarenka, who was struggling with a neck problem, 6-2, 6-2, to book a quarter-final with unseeded Madison Keys.

The Belarusian Azarenka won the Australian Open in 2012 and 2013 but had no answer to the Czech world number four.

“It was really amazing today because she is a champion here and she likes this court, she’s very experienced on this court,” said Krejcikova, who now faces big-serving Keys on Tuesday for a place in the semi-finals.

The American raced past Spain’s Paula Badosa, seeded eight, 6-3, 6-1.

“Absolutely amazing,” said Keys. “I served pretty well and I think I returned pretty well.”