The Brumbies nearly frittered away an 18-point second-half lead but held on to defeat the Rebels 31-21 in their first Super Rugby AU game.
The Rebels scored 17 unanswered points and Matt Toomua's third penalty with nine minutes to go brought them to within a point.
However, Will Miller scored the Brumbies' fifth try of the evening with three minutes remaining to ensure the Rebels came up short.
Two penalties from Toomua - playing his 100th game for the team - were all the Rebels had to show for their first-half efforts, with Andy Muirhead, Joe Powell and Folau Fainga'a going over to leave the Brumbies in charge.
They led 24-6 when Tom Wright crossed early in the second half, yet the Rebels came roaring back through tries from Jordan Uelese and Dane Haylett-Petty, both of which were converted by Toomua.
Yet a poor lineout from Rebels debutant Efi Maafu was seized upon by the Brumbies, and flanker Miller burrowed over to end any hopes of a comeback.