Petra Kvitova was dumped out of the Australian Open as Daria Gavrilova again showed her capacity to pull off a shock with an impressive 6-4 6-4 triumph on Margaret Court Arena.
The sixth seed in the women's draw, Kvitova is a former semi-finalist at Melbourne Park and two-time Wimbledon champion but she was made to pay for a string of errors in the second round on Wednesday.
Gavrilova, a Russian-born Australian, twice came from a break down to take the first set, before holding her nerve to record a popular triumph - and a fourth win against an opponent ranked inside the top 10 during the past 12 months.
After making an encouraging start to the match, Gavrilova gifted Kvitova the initiative by serving three consecutive double faults in the fifth game, her rhythm perhaps disrupted by an earlier foot fault.
However, Kvitova was twice unable to consolidate breaks and a resurgent Gavrilova reeled off 12 points in a row to move ahead.
Kvitova, who appeared unhappy when she was hit on the right leg at the net by a Gavrilova volley that sealed the ninth game, was the architect of her own downfall - a loose forehand that ended the first set represented her 17th unforced error.
Another mistake on the forehand wing gave Gavrilova a crucial advantage in the second set and the home favourite broke again to reach the third round for the first time in a grand slam, after initially failing to serve out the match.
Gavrilova - 3
Kvitova - 1
Gavrilova - 11/20
Kvitova - 17/35
BREAK POINTS WON
Gavrilova - 5/6
Kvitova - 3/4
FIRST SERVE PERCENTAGE
Gavrilova - 62
Kvitova - 65
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Gavrilova - 73/36
Kvitova - 51/43
Gavrilova - 69
Kvitova - 56