The Brumbies were upbeat when they returned to Canberra on Sunday after a brave bonus-point loss to the the Canterbury Crusaders in Christchurch.

But many were still scratching their heads after referee Glen Jackson's bizarre reasoning for giving winger James Dargaville a yellow card in a match-defining decision.

Dargaville collided with Crusaders fullback Israel Dagg, who jumped above Dargaville to take catch a mid-field bomb.

Dargaville was unaware of Dagg's presence because he had locked his eyes on the ball and raised his arms in anticipation of catching it.

Jackson said Dargaville "wasn't in a position to catch the ball" despite replays showing the opposite, and the Crusaders scored a crucial try while Dargaville was off the field.

Larkham conceded the Brumbies had other opportunities to snatch a rare win on New Zealand's south island, but the try in Dargaville's absence played a major role in the Crusaders' 17-13 win.

"I think it was a bit unfair, James Dargaville certainly had eyes for the ball and was just under the ball," Larkham said.

"Clearly from our perspective, it shouldn't have even been a penalty so that's disappointing.

"Could it have changed the game? I don't know. There are plenty of other aspects of the game we need to worry about than refereeing decisions.

"I think the referees have spoken about it. You've got to take care when someone goes up for the ball but you should have equal rights to catch the ball. In my eyes, that's what happened."

The Brumbies took the first step to proving their doubters wrong with an impressive performance against the Crusaders, highlighted by desperate defence and a refusal to roll over.

Their next challenge is a home clash against the Durban Sharks at Canberra Stadium on Saturday night.

Wallabies prop Scott Sio is still recovering from a hamstring injury and is unlikely to play against the Sharks at Canberra Stadium, but versatile back-rower Jarrad Butler could come into selection contention.

The Brumbies showed plenty of promise in their first outing as a new-look unit, but they were starved of possession and couldn't find attacking fluency.

When the Brumbies did hold on to the ball they looked like a slick unit capable of dismantling opposition defences, highlighted by lock Rory Arnold's try to give his team a chance of victory.

"It was disappointing to get so close, but we'll take a lot of confidence out of that and build into the Sharks game," said Brumbies prop Ben Alexander.

"I thought we showed a lot of character and determination, which will put is in a good position. we just need to add a bit of polish."

Perhaps the biggest moment of the Brumbies' season-opener came when Christian Lealiifano ran on to the field just six months after being diagnosed with leukaemia.

Lealiifano is in remission after a bone-marrow transplant and was a surprise addition to the Brumbies squad as a superstar waterboy.

His presence helped calm the nerves of rookie playmaker Wharenui Hawera and the teams inexperienced halves.

The two flyhalves - Hawera and Isaac Thompson - and two scrumhalves (Joe Powell and De Wet Roos) that played against the Crusaders have just 14 Super Rugby games between them. Of those 14 caps, Powell has 12.

It is still unclear if Lealiifano will be able to make a playing comeback this year, but Larkham said the team's co-captain would continue to play a crucial role.

Lealiifano will travel with the Brumbies if his heath permits and will be in charge of running the kicking tee to Hawera.

"I was impressed with all of our guys [against the Crusaders], Wharenui probably fell off a couple of tackles, which he knows. But held his composure during the game and sparked the attack in the second half," Larkham said.

"I thought it was a tremendous first-up Super Rugby appearance."

SUPER RUGBY ROUND TWO

Saturday: ACT Brumbies v Durban Sharks at Canberra Stadium, 7.45pm. Tickets from Ticketek.