Roosters lock Isaac Liu has started all four of the Roosters' matches so far in 2015.

Young Roosters lock Isaac Liu has been an unsung hero during his club's successful run through the opening month of the competition.

With New Zealand Test duo Sonny-Bill Williams and Frank-Paul Nuuausala both departing the Tricolours at the end of last year, Liu has been promoted to the starting team for all four of the Roosters' games so far in 2015, having only done so once previously in his career.

"It was touch and go there for a while but when I found out that Frank-Paul was leaving the Roosters in the off-season I put my hand up to replace him. Trent Robinson spoke to me and said there's a chance there to be taken and I suppose I've made the most of it so far," Liu told NRL.com. 

"Being coached by 'Robbo' is really good, he has helped me out with my playing style and he's given me guidelines on how to be a great lock and I'm just constantly trying to meet them."

Usually playing just over a half of football in his current role at the Roosters, the Samoa international is averaging 65.3 metres and 23.5 tackles per game – a significant improvement on last season. 

However with greater responsibility comes great scrutiny on Liu's performances, something the 23-year-old is wary of.

Mindful of keeping the middle of the paddock tight in defence, Liu is getting used to sticking tough in the opening exchanges of matches.

"I've just trying to find my way in that starting team and get a feel for it while also trying to own it at the same time. I normally played prop off the bench so I'm getting used to I suppose hanging around the middle a bit more now in lock," Liu said.

"At first it was pretty tough but as I've gotten used to it I've been feeling OK. The more minutes you play the more comfortable you get."

A driving force to succeed lies in Liu's desire to win a grand final himself, after he and Dylan Napa were replaced by Boyd Cordner and retired hard man Luke O'Donnell in the final 17 for the Roosters' 2013 grand final triumph.

While he has overcome the disappointment of his demotion, Liu said now with his greater role in the team he is looking to finish the season on the top of the NRL mountain.

"This is my chance to play hard and do what I can to get the Roosters and help the boys back to winning grand finals. It doesn't sting as much anymore that I missed out back then. I've definitely moved on from that," Liu said.

"What it has done for me though is give me motivation to achieve. Knowing the club has been there before, and knowing we have the talent, helps me think we can make it back there.

"I love this whole club, its atmosphere and everyone here is just family. Everyone looks after each other and there are definitely tighter bonds here than anywhere I've played previously. The culture here is just friendly and really welcoming."