The Brumbies stretched their winning streak to six matches while the Hurricanes rallied to stun the Blues ahead of the Super Rugby play-offs.
Already certain of finishing third in the overall table, the in-form Brumbies were aided by the early sin-binning of Reds prop Taniela Tupou in a 40-27 win.
The yellow card wiped out a second Reds score that would have made it 12-0, with Andy Muirhead quickly crossing at the other end for the first of six tries from the home team.
Departing Reds back-rower Scott Higginbotham was also sent to the sin bin in the second half as they slipped to a 10th loss of the season, while their opponents appear in prime form ahead of a play-off tie at GIO Stadium next weekend.
Earlier on Saturday, Hurricanes appeared in danger of slipping to defeat when they trailed 24-5 against their New Zealand Conference rivals at the break, Tanielu Tele'a, Caleb Clarke and Melani Nanai all crossing for the visitors.
However, coach John Plumtree made use of a powerful bench to turn the game around in the second half, running in three tries without reply to steal the win in Wellington.
Jackson Garden-Bachop converted on each occasion and also slotted over a 76th-minute penalty for a Hurricanes side that will be back at home for a quarter-final tie.