Brad Thorn has cast serious doubt over his immediate coaching future after the Queensland Reds unravelled to hand the ACT Brumbies their first win in Brisbane since 2015.

The Reds led 17-15 just before the break but lost their way in the second half, defeated 52-24 at Suncorp Stadium in a Good Friday meltdown that left the proud coach "gutted".

Dual code marvel Thorn has overseen a cultural overhaul since taking the reins in 2018, blooding a host of raw talents and lifting the Super Rugby AU title in 2021.

But at 2-5 and likely to be out of the top eight by round's end, he said he had "possibly" taken the side as far as he could.

"Tonight hurts because it (a heavy loss at home) can't happen," said Thorn, who is off contract after this season.

"End of the day it's on me. I'm a fighter by nature, I like challenges, but it's a disappointing one tonight.

"I like to contribute. When it's not going so well, it's tough."

Thorn said last week he hadn't given proper thought to his next move after 30 continuous years as a rugby league or rugby union player and coach.

On Friday night he looked a beaten man, but when asked if he expected to remain in the job for the back half of the season, he replied: "I'm not a quitter."

"Who knows in coaching," he said. "I'm not a quitter; I'll continue to put my heart in and that other stuff's out of my hands."

The Reds started sharply and led 14-7 when halfback Tate McDermott ran 55m and beat five men to score a terrific solo try.

But again indiscipline haunted them, with Angus Blyth red-carded in the eighth minute for a high shot on Corey Toole that could lead to him being suspended for the rest of the regular season.

More penalties piggy-backed the Brumbies forward and a late try while down a man themselves - after Tom Wright was yellow carded for a professional foul on a rampaging Jordan Petaia - gave the visitors a surprise halftime lead.

They scored five tries in a one-sided second half as the wheels fell off for the hosts in their first loss to an Australian side at Suncorp Stadium in 15 matches.

Brumbies five-eighth Noah Lolesio - like McDermott overlooked for Eddie Jones' first Wallabies squad - controlled the game superbly and kicked all seven attempts in his own statement performance.

The hoodoo-busting win improved the Brumbies to 6-1 and second place on the live Super Rugby Pacific ladder.

Coach Stephen Larkham stuck up for the Reds, echoing Thorn's contention the side was better than their current standing.

"It's a tough one isn't it? Small margins really," Larkham said of a Reds side who have suffered narrow losses to the Rebels and Crusaders in recent weeks.

"I don't think they deserve to be where they are on the table.

"Tonight it was only at the 70, 75th minute mark that we felt comfortable."

Larhkham said if he were Thorn, he would "like to know that the people around you are supporting you".