The world number one endured a couple of wobbly moments in the contest but always looked in control after breaking in the first game, ultimately storming to a straight sets victory.
American Keys managed to serve to stay in the match at 5-3, but Barty - who won 86% of her first-serve points on the day - eased past her under-performing counterpart as she continues her quest for a maiden Australian Open title.
"It's unreal, it's just incredible. I love coming out here and playing in Australia. I'm just happy that I get to play my best tennis here," Barty said during her on-court interview after the win.
"The conditions were really different tonight - this is Brisbane weather. I just tried to adapt and make as many balls as I could. Maddy has the ability to take it away from you really quickly.
"It's just so nice to see her [Keys] back where she belongs, she's an amazing human being. You see the way she carries herself on the court, she looks you in the eye and gives you a handshake and a lot of the girls really respect her."