Manly's hat-trick star Reuben Garrick has dedicated his 20-point haul against Parramatta to the memory of his grandfather and role model David Yates after tragedy struck his family for the second time in a month.

Garrick received news of Yates's death on Friday, but vowed to play in Sunday's thumping win over Parramatta to honour the man who religiously attended his junior games on the NSW South Coast.

Only last month the Sea Eagles were wearing black armbands after Garrick's 10-year-old cousin Kye Yates was pinned under a quad bike near Nowra in an accident on the June long weekend.

Manly welfare officers have been at the ready and teammates, led by housemate Corey Waddell, have rallied around Garrick given the toll the past month has taken on him and his family.

But Garrick was the toast of Brookvale on Sunday with an impressive three tries and four goals in the Sea Eagles 36-24 triumph, an effort he says Yates would have been chuffed about.

"It's been a tough weekend for myself and my family," Garrick told NRL.com.

"I was very proud of the team and I think my grandfather would be proud of our performance.

"He was a great role model for myself and he's what always pushed me forward in footy. He came to every game I played so it was pretty special to get a win in his honour.

"He came to every game and definitely pushed me to play my best and back myself every week.

"He was the biggest role model for me, not only in footy but in life. it was gut wrenching to find out the news on Friday but he'd be very proud at the moment."

Garrick's latest points haul continues an impressive rookie season for the 22-year-old, who is providing serious value for money for Des Hasler after being picked up from the Dragons.

NRL.com understands the Gerringong junior initially had a verbal agreement to a three-year contract with Trent Barrett to join the Sea Eagles when he was still at the helm last year.

But with Manly's coaching shake-up Garrick's deal was trimmed back to one year.

He's since proved his worth and been extended through on the original terms, until the end of 2021, with the fight for a first-grade spot under Hasler pushing Garrick to greater heights.

"You can never take for granted what you have in the contract," Garrick said of his re-signing.

"I was so excited when I found that out and it shows in my footy, I think it gives them a lot of confidence in the decision as well.

"I'm a very competitive person and I knew that once I was given the opportunity to come up here and have a pre-season, I'd train really hard and just try to beat my opposite numbers.

"I was really excited to come up here and play under Des. He's such a well-regarded coach and a grand final winning coach so as soon as I found out he was coaching at Manly, I was so excited, and he's helped me so much this year."