While 16 Roosters go cock-a-hoop in the corner of ANZ Stadium, Cooper Cronk slumps exhausted in a plastic chair on the sideline.

His shoulder is going to be useless for the next couple of months.

It already was for the preceding 78 minutes, a fair shout given the damage it bore is usually only associated with a car crash.

So for the next two minutes, Cronk sits. And great mate Matt King sits with him.

Now an assistant on Trent Robinson's coaching staff, King knows Cronk from their formative years at Norths Devils, Melbourne's old feeder side.

When Cronk was an apprentice plumber, and King a garbage man both trying to crack an NRL contract, their toil a rugby league's lifetime away from Cronk's grand final heroics.

They're only 50-odd metres away from their clubmates going collectively spare, but these two just sit. And it's priceless.

"He'd achieved the unthinkable," King told NRL.com.

"It dawned on him. Everyone gave him a cuddle and then they left him and I was just there with him.

"Coops has been a great friend of mine ever since 2003 when I first arrived at Brisbane Norths.

Robinson on Cronk: "Legend status"

"We were there together and what he went through this week, I just wanted to take a moment with one of my best mates, to give him a cuddle and just let him know that I was in proper love with him.

"I was in awe of what he'd done tonight.

"I knew there would be cameras, I just said to him 'stay here as long as you want'. Don't forget this. And he did, he soaked it in and he deserved it."

Cronk will go down in rugby league folklore too, deserving every accolade that comes his way as the game fawns over a remarkable display of resilience.

King was around the Rabbitohs in 2014 when Sam Burgess won a Clive Churchill medal, despite playing 80 superb minutes with fractured eye socket and cheekbone.

And in his eyes, Cronk trumps the indomitable Englishman.

"It's the toughest thing I've ever seen," King said. "Usually you break your scapula, which is muscle-bound and protected, when you're in a car crash.

"To rise above that pain is one thing, the pain killing needles obviously helped that.

Roosters continue the party with their fans

"But that mental capacity to say: 'I'm playing in a grand final, I know that Nelson Asofa-Solomona, Joe Stimson and all those big blokes are going to come at me and I'll be in a sling for however long afterward', that's astounding.

"I was a part of the Rabbitohs when Sam broke his cheekbone and played the full 80.

"What Cooper went through this week has got him covered. Toughest thing I've ever seen.

"What Coops did, is just incredible".