Jamayne Isaako has paid tribute to Jack Bird for his own stunning display at fullback in the round win over the Cowboys.

Bird had initially beaten the Kiwi international to the coveted number one jersey in a late pre-season surge before tearing his ACL at training last week.

That gave Isaako the chance to move up from the bench to start in the custodian's role where he was a standout in Brisbane's 28-21 win in Townsville where he made 17 runs for 176 metres, created two line breaks and set up a try.

"It was sad seeing Birdy go down at training and I really felt for him when he went off with his injury because we know how hard he had worked coming back from his ACL injury last year," Isaako said.

"I'm glad we were able to get the win. We were thinking about Birdy before we went out there.

"Over the pre-season everyone has been battling for spots and when Birdy came into the picture for fullback I know we both pushed each other at training over that last bit of pre-season.

"Obviously I was happy for him when he got named at fullback because I know how hard he has worked over the pre-season. It sucks personally when you don't get picked in the starting lineup, but I knew I had a job to do."

Match Highlights: Cowboys v Broncos

The 23-year-old did not kick stones when he realised Bird had initially edged him out of the role. Instead he applied himself even more and had a mindset against the Cowboys of running the ball first and foremost. Isaako is a confidence player and he showed a willingness to back his natural instincts.

"When you are battling for a spot and you don't get picked I think the motivation is to work harder and push for a spot. I went out there and practised what I did over the pre-season," Isaako said.

"Nothing was new for me. I just did what the coach asked me to do and that was to play footy and have fun.

"A lot of our game plan and our structure around our attack is for our fullbacks to run the ball a bit more and look to run first. I did that tonight and ran off the back of Brodie [Croft]  and Milly [Anthony Milford] and I think we did a really good job."

Isaako was in awe of the 70-metre solo try that back-rower David Fifita scored in the second half and would have been in support of him if not fort the cramps that he sustained as the match wore on.

Fifita continues to do the impossible

With the 20-year-old off-contract at the end of the year Isaako said it was vital Fifita's future was at Red Hill and not with any of the other clubs that are in a race for his signature.

"It is really important [to keep Fifita] I think," Isaako said.

"He is one of the up-and-coming young players in our team.

"I was speaking to him, I don't know whether he is going to stay or go. That is a decision he is going to have to make. We will just support him."