The Queensland Reds humbled Super Rugby leaders Golden Lions 27-22 after a superb opening half of aggressive rugby in Brisbane on Saturday.

The Reds, coming off four losses, set up their shock win with a rousing four-try first half to lead 24-0 at half-time and battled hard to hold on in the second half to bring off the upset.

It was a stunning reversal of fortunes for the South African conference leaders and last season's beaten finalists following their 29-0 shut-out of Australian conference pacesetters New South Wales Waratahs in Sydney the previous week.

The Reds, coached by former All Black lock Brad Thorn, jumped to third spot in the Australian conference while the Johannesburg-based Lions still hold a 12-point lead in their conference.

"Last week you could tell quite early we weren't quite there, but this afternoon that first try in the first five minutes was indicative of how we wanted to play, be aggressive in the contact area," Reds veteran flanker George Smith said.

"We came out well for that first 10 minutes of the second half and we were holding on in the last 30."

Lions skipper Franco Mostert said the Reds were more hungry to win than his team.

"They wanted it more than us, so they deserved the win, there was no complacency in our group, they just wanted it more than us and we will go back this week and fix up our problems," Mostert said.

The Reds rocked the competition leaders with four tries in the first half in their best attacking performance of the season.

Forward Jean-Pierre Smith scored in the second minute with further tries to Caleb Timu and Brandon Paenga-Amosa before Smith crashed over on the back of a driving maul in first-half stoppage time to grab a 24-0 lead at the break.

The spluttering Lions finally scored through their outstanding hooker Malcolm Marx to trail 27-5 after 55 minutes.

Marx powered over for his second try off the back of a driving maul for the Lions to claw back to trail 27-12 after 62 minutes with the momentum turning.

But the Reds held on with replacement Marnus Schoeman scoring two late tries to grab the Lions a losing bonus point.