The Brumbies' late-season surge towards the Super Rugby finals has been halted by a 24-19 loss to the Chiefs in Hamilton.
Needing a fourth straight win on Saturday to keep their unlikely playoff hopes alive, the 10th-placed Brumbies looked buried at 24-5 well into the second half.
However, they stormed home with two late tries and threatened to snatch victory when sweeping downfield in the final play before a contentious knock-on call from South African referee Rasta Rasivhenge.
"I'm incredibly proud of our effort. I thought we had belief right to the end," Brumbies captain David Pocock said.
"But against a team like the Chiefs, a few lapses and they punish you. They're an incredibly classy team."
The Brumbies are five points behind the eighth-placed Melbourne Rebels and will need a big win over the Waratahs next week to move ahead of them on points differential. They'll also need other results to go their way.
Dan McKellar's men dominated the second half against one of the competition's premier sides, just as they did when upsetting the Hurricanes last week.
Pocock was magnificent all around the park while winger Henry Speight crossed for two tries on a ground he once graced at provincial level for Waikato.
The other second-half Brumbies try went to outstanding fullback Tom Banks but it wasn't enough to overcome the Chiefs, who kept their nose in front through a try to reserve back Johnny Fa'auli midway through the second spell.
Nothing went the Brumbies way in the first half, losing flanker Tom Cusack to injury. He clashed heads with teammate Rory Arnold in key moment, the pair then falling off hooker Nathan Harris as he scored the Chiefs' first try.
The second went to brilliant playmaker Damian McKenzie, who finished with 14 points and was the one player to make regular punctures in an otherwise industrious Brumbies defensive line.
Chiefs reserve forward Jesse Parete was shown a yellow card late in the second half but Pocock was adamant there should have been more. The Wallabies flanker constantly asked Rasivhenge why he wasn't punishing the Chiefs for persistent offending.
The Chiefs remain locked with the Hurricanes in a fierce battle for second place in the New Zealand conference.
Those teams meet next week in a match to determine which team is ranked fourth overall and hosts a quarterfinal.