Barty lost just 10 points in her first-round win against Danka Kovinic and the world number one got past Gavrilova 6-1 7-6 (9-7) on a warm and breezy Rod Laver Arena.

But she struggled to close out her fourth victory in five meetings with her fellow Australian amid worries over heavy strapping on her left thigh.

She will face either Barbora Krejcikova or Ekaterina Alexandrova in the third round, which she reached at Melbourne Park for the fifth straight year.

Barty was broken in the first game after three unforced errors, but Gavrilova was unable to consolidate and it proved costly.

A double fault from Gavrilova handed Barty a 3-1 lead and the 2019 French Open champion capitalised to claim the first set in 27 minutes.

Barty served three double faults in the second game of the second set, yet she again broke back immediately and proceeded to take a 5-2 lead.

But the contest started to turn from then as Gavrilova reeled off four straight games, with errors proving costly for Barty.

However, a pair of forehands into the net saw Gavrilova squander two set points in the tie-break and she was punished as Barty finally closed out victory.