Rod Laver Arena/Melbourne Park, Melbourne VIC 3000, Australia, 20 January 2016 | AAP

Daria Gavrilova stunned sixth-seed Petra Kvitova to march on to the third round of the Australian Open.

Gavrilova upset the two-time Wimbledon winner 6-4 6-4 in 89 minutes to book a date with Kristina Mladenovic in the last 32 at Melbourne Park.

The win ranks as one of Gavrilova’s best, perhaps behind only a defeat of then-world No.2 Maria Sharapova in Miami last year.

“It was unreal,” Gavrilova said. “I was so nervous at the end. I’m just really proud.”

Gavrilova and Kvitova traded heavy groundstrokes in a high-quality meeting.

The effervescent Gavrilova was broken twice in the first set. But each time she responded to break straight back, with her fist-pumps becoming more frequent as she grew in confidence.

In a faultless end to the set, Gavrilova won three games without dropping a point to carry all the momentum into the second set.

A key moment then arrived at 2-3, with Kvitova twice double faulting and making two errors to give away her serve.

Gavrilova served for the match at 5-3 but wobbled, losing the next three points to put the match back on serve.

In front of a vocal crowd, Gavrilova calmed her nerves and broke straight back to reach the third round of a major for the first time.