Barty used her all-court game, full of all manner of spins and angles, to great effect as she started and finished the match in dominant fashion.
"She's a fighter, a great competitor and she will be sorely missed," Barty, who showed no sign of the hip injury that forced her to retire hurt at the French Open, said on court.
The Australian opted not to try and defend her title last year, citing concerns over the COVID-19 pandemic and a lack of training time in an abbreviated season.
"I've only played her a couple times. We haven't played a lot," Barty said, adding she had not watched Saturday's final between Osaka and American Jennifer Brady.
"She's (Barty) looking forward to playing against her. It's a great test because she is such a quality player, obviously improved out of sight from back then to where she is now."
Djokovic earlier told reporters he had taken a walk in a park to celebrate his release from the 14 days of quarantine players coming from overseas were obliged to undergo to play in Australia.