A last-minute win made the Brumbies' round-one wobbles a little easier to watch on Monday, but Swain says they cannot afford to make the same mistakes when they play the Fijian Drua on Saturday.

The Brumbies' lineout failed to hit its mark in the opening-round win against the Western Force, crippling their attacking opportunities and forcing them to make six times as many tackles as the visitors in the first half.

In fact, the Brumbies had the second worst lineout completion rate of all games in the opening round after winning just 69.2 per cent of their throws.

It shocked most because the Brumbies have used the lineout as the cornerstone of their game for several years to either go to the rolling maul or use it as a back-line platform.

But it wasn't all bad. The Brumbies still scored four tries, made the second-most clean breaks (six) and were second in offloads (11) behind only the Waikato Chiefs.

Swain threw up his hand to take responsibility for the early lineout struggles, saying some of his calls put hooker Folau Fainga'a under too much pressure.

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They were able to make changes on the run to avoid complete disaster and Swain said they were wary of giving the unpredictable Drua open-field chances.

"There's a lot of things we can improve on, set-piece in particular," Swain said.

"I didn't call great at the start [of the game against the Force], which put the team under pressure and put Folau under pressure by [asking him] to throw some big ones.

"We just need to value possession a bit more. There was one point at half-time when we'd made about 120 tackles and they'd made 19. That's ridiculous ... we've just got to be better than that [even though] we found a way [to win] in the end.

"We always speak about having a world class set piece. We've just got to go back to trusting what we do."

The Brumbies had to come from behind to beat the Force by six points, reserve hooker Lachlan Lonergan crossing the line to snatch victory as time ran out.

It was a crucial win in the context of the season, even though it was the first game of a new Super Rugby Pacific competition.

A loss would have put them behind the Force, Queensland Reds and NSW Waratahs in Australia and although there is no longer a conference system, winning home derbies is still going to be a major factor in title aspirations.

Coach Dan McKellar and captain Allan Alaalatoa warned mistakes needed to be eliminated against the Drua - one of two new teams in the competition - this weekend.

"We can't make too many mistakes, we want to give them the ball on our terms because they're ruthless on unstructured attack," Alaalatoa said.

The Fijians showed glimpses in their first-round loss to the NSW Waratahs, beating 19 defenders to be ranked second of all teams.

But they scored just one try and ultimately failed to fire in the defeat, which McKellar and Swain say makes them a dangerous proposition in the capital.

"In the past when we've played the Fijian Drua side in the NRC, we've always harped on about set piece and having a really structured game, and making sure we're physical, because they'll be physical too," Swain said.

"[Against the Waratahs] they threw the ball around, but at the same time their set piece wasn't great. Their maul got demolished.

"[But] if we're playing on the backfoot, they'll just start doing what they do with those silky offloads and running through us. You'll see plenty of that if we're not physical."

SUPER RUGBY ROUND TWO

Saturday: ACT Brumbies v Fijian Drua at Canberra Stadium, 2pm

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