Slater squared off with Tedesco in last year's grand final - his final game before retirement - with the Roosters No.1 then taking over the Storm gun's top custodian title.

Slater is urging Papenhuyzen to try to put all thoughts of a match-up against the game's best fullback out of his mind in their SCG clash and just concentrate on doing his job for the Storm.

With Papenhuyzen playing in his first finals series after making his NRL debut in round four, Slater's tip for the 21-year-old is to not focus on Tedesco.

"That's probably the biggest thing," Slater told AAP.

"The build-ups between match-ups like that are obviously huge and you want to play well against the good players but it's important that he (Papenhuyzen) focuses on what he's doing well.

"His role doesn't change; he just needs to look to how he's contributing to the team's success and getting the team in good positions and what he's doing for the Melbourne Storm rather than trying to use it as a battle against the No.1 fullback in the game."

Slater has been a regular observer at Storm training this year and has had a major hand in Papenhuyzen's development.

With the youngster starting his fifth successive game at fullback, Slater said his improvement had been noticeable.

Indeed his figures in four recent starts at fullback stack up well against Tedesco.

Comparing the past three rounds of the competition and the qualifying final, Papenhuyzen has made 83 runs for 868m with seven linebreaks while the NSW Origin star has had 70 runs chalking up 785m, also with seven linebreaks.

"It's been huge for sure," Slater said.

"Ryan's got a really good attitude, which has been the trait to get him into this situation because he wasn't in line to wear the No.1 jersey but through sheer will and determination he's demanded a spot in the team."

Slater said that Tedesco's game had gone to a new level when he joined te Roosters and had the likes of Luke Keary, Cooper Cronk and Boyd Cordner around him.

He felt Papenhuyzen would show similar growth with more time spent in the Storm inner circle.

"He's a great runner of the ball and he's already got a passing game, and that's going to develop, but for him to be doing what he's doing, with 22 games under his belt and only a handful of those at fullback, he's extremely developed," Slater said.

Australian Associated Press