The Brumbies won a blood-and-guts derby to deny the NSW Waratahs outright top spot on the Super 14 table on Friday night.

Second-half tries to winger Adam Ashley-Cooper and prop Ben Alexander secured the Brumbies a vital 21-11 victory in a torrid encounter at Canberra Stadium.

The win came at a price, though, with skipper Stephen Hoiles limping off with a potentially serious knee injury and several teammates left battered and bruised.

Lock Mark Chisholm was floored trying to bring down Waratahs counterpart Will Caldwell, while fellow Wallabies forward George Smith was one of several players left spitting blood.

The Waratahs had their own casualty ward, with replacement hooker Adam Freier lasting a matter of minutes before trudging off with a possible broken collarbone.

Fullback Sam Norton-Knight spent time in the blood bin after having his head split open and five-eighth Kurtley Beale was left bleeding from the mouth after being taken out by Hoiles.

But it was the Brumbies smiling at fulltime after ending NSW"s undefeated start to the season - and climbing to the cusp of the top four with their third win from four starts.

Resuming their campaign after suffering only their second home loss against an Australian province in 14 years of Super rugby, the Brumbies were clinging to a 6-3 halftime lead courtesy of penalty goals to fullback Mark Gerrard in the 10th and 33rd minutes.

NSW's only points in the first half came seconds before the break when Beale finally found his range with his fourth penalty-goal attempt - having struck both uprights with earlier shots.

Watching from the stands, Wallabies coach Robbie Deans would have been enthused by the two sides' willingness to chance their arm in the opening quarter of an hour before the tempo slowed, mistakes crept into the game and the niggle began.

Hoiles and Waratahs flanker Dean Mumm were cautioned for some push and shove midway through the half and then Hoiles flattened Beale in an off-the-ball shoulder charge.

The Brumbies scored the first try of the match five minutes into the second half when Stirling Mortlock - running freely back at outside centre - put Ashley-Cooper over in the right corner.

But no sooner had they jumped to their eight-point advantage were the Brumbies on the back foot, with Hoiles and Chisholm both forced out of the action.

Despite Beale edging NSW back to within five points of the Brumbies, the home side rallied and rewarded with their second try in the 62nd minute when Alexander burrowed over.

The try, though, belonged to side-stepping centre Tyrone Smith, who stood up Timana Tahu and then bumped off Beale in a surging run to take the Brumbies deep into Waratahs territory.

A third Gerrard penalty goal sealed the deal before the Waratahs grabbed a consolation try through winger Lachie Turner three minutes from time.

Brumbies coach Andy Friend was delighted at how his team bounced back from the bye and a fortnight of soul searching following their disappointing 25-16 loss to the Western Force.

"It was a shift in attitude," Friend said.

"The two weeks we just had we asked some good questions of each other and we answered those questions tonight.

"I thought they showed a lot of character, which was good, and we've just got to make sure we keep that happening every time we play.

"Tonight they (the Brumbies) definitely had a different approach in the change room and you could sense they were ready for a battle ... I was really proud of them."

Waratahs coach Chris Hickey admitted the Brumbies were too physical for his side.

"All credit to the Brumbies. They were very good at the breakdown and I thought that we probably got out-enthused and out-muscled there," Hickey said.

"We were pretty happy with the first half but the second half our defence fell away.

"They aimed up at the breakdown and that was the significant aspect in the game.

"We were up for the game. Our preparation was good. Obviously the Brumbies' preparation was very good."

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