Angelique Kerber continued her return to form by clinching her first title of the season on Saturday, beating Ashleigh Barty in straight sets, 6-4, 6-4 at the Sydney International.
It was Kerber's 11th career title.
The German made her breakthrough in 2016, with wins at the Australian Open and Flushing Meadows, but struggled previous year, falling to 22nd in the world.
"I am playing awesome tennis again and I am just feeling great". Today Kerber won 74% first serve points, and saved five break points out of six.
De Minaur, ranked 167 in the world and the youngest player to reach an ATP World Tour final since American Taylor Fritz at Memphis in 2016, showed impressive fighting spirit to recover from 4-0 down in the decider to level the third set at 5-5.
Barty held just once in the first set but reversed the momentum in the second when she broke in the ninth game after Gavrilova double faulted twice, which prompted the 23-year-old to smash her racquet in frustration and earn a code violation.
The former world No.1 was too strong for Barty, winning the final 6-4, 6-4 to give her a massive confidence boost for next week's Australian Open in Melbourne.