When a fresh-faced 20-year-old Billy Slater picked up the ball from dummy half in his debut NRL game and weaved a magic run to the try line, Cameron Smith knew his mate would make it as a professional footballer.

"We were playing Cronulla and getting beaten quite convincingly," Smith said of the 2003 opening-round clash.

"I remember Billy picking the ball up from dummy half, and I think he beat four or five defenders to score in the corner to try and get us on the front foot.

"You think, 'wow, he's beaten some quality first-graders here, in his first game. This bloke could be pretty special'."

Smith and Slater played together for the Brisbane Norths under 19s a couple of years earlier. Now, 15 years later, the Melbourne Storm fullback will finally join his mate in the 300 club.

"It's been a long time coming," Smith said.

Billy Slater in his NRL debut in 2003.
Billy Slater in his NRL debut in 2003. ©NRL Photos

"I was talking to him after our session yesterday afternoon, and he told me in 2015 or the end of 2014 he was up to 270 matches, so it's taken him a long time to make up that (extra) 30.

"I'm glad now he gets that opportunity to do that. For what he's done for this club and the game overall, he deserves to be in that special group to reach 300. He's had injuries in his career - knees and groin issues, and the latest (being) two shoulder surgeries to go through.

"He didn't even know if he was going to play football again, so for him to go back and have the year that he had and play his 300th is really special."

Cameron Smith and Billy Slater.
Cameron Smith and Billy Slater. ©NRL Photos

Smith believes Slater's communication at the back has made him such a dominant fullback over a long period.

"I think the greatest asset he has, you don't see or hear," Smith said.

"He's continuously talking to me over my shoulder when we've got the ball, telling me about the position of the defence, and where their fullbacks and wingers are. He's constantly giving you advice on where we need to go.

"Particularly in defence, he's the one that positions all of our players around the field. That's what separates him as a fullback. Take away all the tries, try-assists and line-breaks, the way he positions the team around the field is the best that I've seen."

While there's a lot of focus around Slater's Telstra Premiership milestone at the club this week, Smith knows there's enough to work on if they want to make it a winning start at home on Saturday night against the Wests Tigers.

"The pleasing thing was we played some pretty good footy with the ball (against the Bulldogs in round one), but there's also a lot of things we were a little bit off in," he said.

"Our first efforts in defence weren't great and in our standards. We've spoken about that in our review before we left. That was the key message out of the game from Craig, we've got a lot more improvement left in us."