Mack Hansen kicked a very late penalty as the Brumbies maintained their unbeaten Super Rugby AU record with a last-gasp 22-20 win over the Reds.

Substitute Hansen was the home team's hero as he slotted over the game-winning kick on the final play of the game, punishing their opponents after an infringement at the breakdown.

The visiting Reds had looked set for victory after overturning a 14-3 half-time deficit thanks to a blistering 10-minute spell that saw them score 17 points.

Harry Wilson and Angus Scott-Young crossed for tries that were converted by James O'Connor, who also added a 50th-minute penalty to extend his team's advantage.

However, the Brumbies, who saw Folau Fainga'a touch down twice in the first half, closed the gap when Connal McInerney scored out wide in the 75th minute of a see-saw battle.

Hansen missed the conversion but was on target when presented with another opportunity after the final hooter, his long-range three-pointer completing the comeback.