Just keep winning. Fainga'a can think of few better ways for the Brumbies to prove they belong in trans-Tasman rugby's new era than conquering their Super Rugby AU rivals.

The 25-year-old says Australian players will want clarity on their future with concerns rising clubs could be culled to fit in with New Zealand Rugby's preferred competition model.

There are concerns up to three Australian franchises could be on the chopping block with NZR planning an eight to 10-team competition for 2021.

But Fainga'a wants to let his rugby do the talking and leave boardroom worries to club bosses as Rugby Australia prepares to meet with their New Zealand counterparts this week to map out a future.

MORE BRUMBIES

It comes as the Brumbies prepare for a clash with the Western Force at Leichhardt Oval on Saturday, an interstate rival with a chip on their shoulder desperate to show they deserve to be on this stage.

"Next year is next year, but for us as a playing group we're just taking it week by week. It is our future, but then again we don't want to look too far ahead with things," Fainga'a said.

"It's up to the person by themselves, myself, I just like to block that stuff out. I just like to concentrate on what's up next and just stay in the moment."

Just as the Brumbies did as they overturned a 15-point deficit to secure a last gasp 24-23 win over the NSW Waratahs at Sydney Olympic Park on Saturday night.

But the elation brought on by Issak Fines' match-winning try with little more than three minutes left on the clock was somewhat soured by a glance at the sideline.

The Brumbies are sweating on scan results which will reveal the extent of flyhalf Noah Lolesio's hamstring injury which forced him off the field during the first half of the Waratahs clash.

Loosehead prop James Slipper will have to undergo concussion protocols this week to prove his fitness after failing a head injury assessment.

Fainga'a did manage to secure a slice of history when he crashed over in the first half to become the first Brumby to score tries in six consecutive games - a feat achieved only once before in Super Rugby.

But his focus remains on rebuilding the set piece for which the Brumbies have become renowned after a scratchy start to the new season.

The Waratahs clinched three scrum penalties and at times dominated an inconsistent Brumbies lineout which has sparked some fear the club's set piece is losing its magic.

But they will enter the Force clash in Sydney buoyed by the fact they are the first visiting team to win a game in the Australian competition.

"We've definitely got a lot to work on, especially up front there. If you don't do what you've trained all week for against a quality side like the Tahs, they'll dish you up," Fainga'a said.

"We've got a lot of learning out of that game. It was a good game to watch and be a part of, there is a lot of emotion every time we come up against the Tahs, obviously being just down the road.

"It's a big confidence boost for the group, we're the first travelling team to win. A couple of hours on the bus up to Sydney, it was a good win for us and we've got a lot of learning to take out of that game as well.

"You've always got to get up for games like this. If you don't turn up against a quality side like the Tahs, they'll sting you and they can keep you scoreless for a while.

"It's all between the ears for us, you just do what you need to do and as soon as you get up here, you switch into game mode."

SUPER RUGBY AU ROUND FOUR

Saturday: Western Force v ACT Brumbies at Leichhardt Oval, 7.15pm.