A Folau Faingaa brain explosion threatened to cost the Brumbies any chance of victory at Loftus Versfeld on Sunday morning when the hooker was sent off in the 61s minute for headbutting Mattys Basson.

The impact of Faingaa's forehead was minimal, but he faces a nervous wait after the moment of madness that could could cost him a chance to play for the Wallabies in the mid-year series against Ireland in June if he's suspended by the Super Rugby judiciary.

But the plucky Brumbies found a way to win with less men on the field, charging from behind to seal a victory that had to be seen to be believed.

The Brumbies trailed by one point when Faingaa left the field and by four points not longer after following a Handre Pollard penalty.

But that seemed to spark the Brumbies, who found confidence despite enduring one of the toughest losing streaks in the club's history.

Tom Banks scored a brilliant individual try to steal the lead in the last 10 minutes and then Andy Muirhead sealed the win when he finished off a move out wide.

It was a sweet end to a two-game tour of South Africa and snapped a five-game losing streak to give the Brumbies some confidence before returning to Canberra to play the Japan Sunwolves.

Faingaa will likely face the judiciary on Sunday night, with red-card offences automatically subject to the tribunal and any suspension could affect his availability for the Wallabies' three-Test series.

But the Brumbies deserve to savour a gutsy win on the road after becoming the first Australian team to win in South Africa this year and delivering a performance that should encourage fans to return to Canberra Stadium to support them.

Banks was a stand out for the second week in a row, the former Queensland Red finishing the tour with three tries in two games and finding his form after a slow start to his second Super Rugby season.

"It's been a long tour, it was a hard effort last week but good to play some running rugby," Banks said.

"It comes down to confidence and belief. Even though we were down to 14 men n the end I think we just stuck to our structure and got the win in the end.

"I'm enjoying it, it was a big move for me to go down to Canberra but I'm loving it."

It was the Brumbies' first win since beating Queensland on April 7. The club is targeting a crowd of 15,000 for their return to the capital and Christian Lealiifano hopes they continue their winning form.

The Brumbies have now moved one point ahead of the Reds on the Australian conference ladder and the players have gained some much-needed self belief.

"Once you get those chances, you've got to finish them off," Lealiifano said.

"The guys finished well [against the Bulls]. I think we've got to improve our defence again, that's something we're constantly working on.

"It's getting there, and just in our attack we've just got to keep believing in our skills. It's quite fun to play."

The Brumbies were sliced open in the fifth minute when Bulls flyhalf Handre Pollared brushed passed two woeful attempted tackles from Scott Sio and Sam Carter to score the opener.

It was the worst possible start for the visitors, but they had the perfect response from the restart. The Bulls lost the ball and Kyle Godwin scored less than a minute after the Brumbies conceded the opener.

It started an arm wrestle of desperation, with both teams keen to chance their arm but wary of giving away opportunities to their opponent.

The end-to-end rugby was pretty to watch and the Bulls took advantage of their opening when flanker Roelof Smith scored out wide.

The Brumbies were stuck in their own half for the next 20 minutes, forced to scramble, scrap and hang on for life as the Bulls peppered away at their line.

They somehow managed to hold on time after time despite getting just 19 per cent of the territorial advantage in the first half.

They got a reprieve and trailed by just four points at the break, but it could have been so much better had Lealiifano nailed an after-the-siren penalty attempt.

They didn't have to wait long to make amends, with Joe Powell spotting a gap at the breakdown and then offloading to Lachlan McCaffrey to steal the lead two minutes after half-time.

A harsh scrum penalty allowed the Bulls to level the score at 17-17 and then a controversial try saw them storm back in front.

Warrick Gelant ran behind one of his own players to streak clear into a gap and offloaded to John-Ben Kotze for a try.

But referee Marius van der Westhuizen deemed defender Godwin was not impeded and awarded the try, only to then penalise the Brumbies for an obstruction from the kick-off.

It threatened to break the Brumbies when Pollard slotted a penalty, but they refused to roll over and got back into the contest when Faingaa scored from close range to close the gap to one point.

It should have been the moment to give the Brumbies hope, but they imploded just minutes later when Faingaa was sent off for headbutting Basson.

But the Brumbies again refused to roll over and a superb Banks individual try and a Wharenui Hawera sideline conversion put them in front by three points with less than 10 minutes to go.

Winger Muirhead then sealed an unbelievable win, flying down the sideline to put the result beyond doubt.

AT A GLANCE

Super Rugby: ACT BRUMBIES 38 (Kyle Godwin, Lachlan McCaffrey, Folau Faingaa, Tom Banks, Andy Muirhead tries; Christian Lealiifano 3, Wharenui Hawera 2 conversions; Christian Lealiifano penalty) bt PRETORIA BULLS 28 (Handre Pollard, Roelof Smith, John-Ben Kotze tries; Handre Pollard 2 conversions, 3 penalties) at Loftus Versfeld, Pretoria, on Saturday night. Referee: Marius van der Westhuizen. Crowd: 8189.