Brisbane forward David Fifita.

Being the cousin of Andrew Fifita didn't stop Brisbane rookie David Fifita from getting "whacked" by the Sharks prop on Thursday night at Suncorp Stadium.

The 18-year-old forward, who became the first player born in the 2000s to play in the NRL when he made his debut against the Canberra Raiders in round 16 and has not missed a game since, played 52 solid minutes against his cousin in the 12-10 win over Cronulla.

He said the 2016 premiership-winner had been an inspiration to him as he aims to make his own mark on the rugby league landscape.

The family shares a close bond that extends well back into the homeland of David’s ancestors.

"We are real close. My granddad and [Andrew’s] great grandad come from the same village in Tonga called Vava'u," he said.

"Every time he comes up here he always keeps me grounded and hangs out with me, and every time I go down there I always try and get the time to hang out with him.

"He is always supportive of me, him and [Andrew's twin] David over in England. They always message me to keep working hard and keep me humble.

"I got whacked by Andrew out there and he was giving it to me, but it is all good. I enjoyed it."

It has been a stellar rise for Fifita from under-18s and Intrust Super Cup with the Souths-Logan Magpies to playing five games straight in the NRL. He insisted that he was adopting a "no excuses" attitude up against players often more than a decade older than him.

"I am only 18 but that doesn’t matter. I can’t use that as an excuse. This is a tough game with the big boys and I’ve just got to keep working hard and do my job," he said.

"I was playing Mal Meninga [Cup] for Souths Logan in the under-18s comp and, if I go back to then, I wouldn’t think I would be here right now. It is just the baby steps that I’ve done. If I am patient, my time will come. Now I have got my opportunity in first grade and I am happy with how I am going."

Signed by Brisbane until the end of 2020, he had no idea he was about to make his NRL debut against the Raiders until football operation manager Scott Czislowski's number came up on his phone on game day.

"I didn’t find out during the week. I was preparing to play for Souths-Logan [against Norths] in the curtain raiser to the Raiders v Broncos game," he said.

"I was in the shopping centre and Scotty called me and said ‘congratulations mate, you’re playing with us tonight’. I called my parents and they were over the moon. I was real happy.

"If I would have known [in advance] I wouldn’t have got to sleep the night before so I am just grateful that Wayne [Bennett] chose me and hopefully I can keep doing the right thing by him."

When Payne Haas made his debut for the Broncos against Souths in round eight it lit a fire in Fifita’s belly.

"We come from the same high school at Keebra Park and I am real proud of him. I was watching him at home against the Rabbitohs and I thought 'I want to be doing that soon' and I got my opportunity," Fifita said.

"I feel sorry for Payne with what happened to him [with a season-ending shoulder injury] but he is a great player and a great mate and hopefully we can do so some damage playing alongside each other in the future."

Veteran forward Sam Thaiday said Fifita's future would be bright.

"As an 18-year-old he doesn’t hold back. He charges in," Thaiday said.

"He plays like he has been playing first grade for a long period of time. It is good to see that he has that confidence and he’ll only get better the more games he plays."