The Brumbies have had their run to the Super Rugby finals spoiled by New Zealand's bottom-ranked Blues, who stunned the Australian conference leaders with a 40-15 bonus-point win in Auckland.
The ACT franchise needed a victory at Eden Park on Friday night to steer clear of a resurgent NSW Waratahs in the race to secure the country's sole guaranteed playoffs berth.
But the loss - their first in five games - keeps them on 39 points and equal with the Tahs, who have an opportunity to leapfrog them into top spot against the Hurricanes at Allianz Stadium on Saturday night.
The Brumbies lead the conference only by virtue of having an extra win, and have just one more game remaining - against the Western Force at GIO Stadium next weekend.
The home side were out of play-off contention and their main motivation was to end the season with a positive record for the first time since 2011.
Blues flanker Jerome Kaino completed a try-scoring double in what was eventful night for the All Blacks loose forward, producing an energetic all-round performance but also being sin-binned in the opening spell.
Wing Matt Duffie also scored a brace as the Blues belied their status as the bottom New Zealand team by dominating from the kick-off.
Kaino got the Blues going, dotting down after first five-eighth Ihaia West found him with an accurate cross kick.
Skipper James Parsons got their second five-pointer, with the hooker finishing off a slick line-out move.
The Brumbies hit back with their big weapon, the line-out drive, which produced a penalty try and a yellow card for Kaino for pulling the maul down.
Despite being a man down, the Blues added tries to prop Sam Prattley and Duffie, which were the result of expansive attacks.
Trailing by 21 points, the Brumbies were able to drag the contest back to an arm wrestle.
Another line-out maul resulted in a touchdown for second-five Matt Toomua, and yet another drive ended in a Christian Lealiifano penalty goal that closed the gap to 28-15 at halftime.
But the Blues moved further ahead through Kaino, ironically off a line-out drive.
They continued to do most of the attacking and Duffie got their sixth try with eight minutes to go.