Bumped out of the Wests Tigers, Farah arrived at the Rabbitohs as an Origin hooker himself with 16 games for NSW.

By then Cook was aged 25 and had only 26 first grade games to his name, having only just claimed a regular starting spot for the first time in his NRL career.

Just four years later, Cook can join Ben Elias and Danny Buderus as the only Blues hookers to win three straight Origin series with a NSW victory on Wednesday night.

"He always had that speed but he probably never really understood the craft of being a dummy-half," Farah told AAP.

"That was something I probably saw develop in him over the 18 months I was at the Rabbitohs.

"He has worked on his defence as well which was something he had to work hard on.

"He brought a kicking game into his game as well. And his deftness with his passing as well.

"He always relied on his speed, but when he brought the other aspects it made him a more complete player."

Cook's rise since 2017 has been well covered.

By five rounds into the season he got his starting spot back. And by mid-2018 he was clearly the game's best running hooker.

He hasn't let the NSW or Australian Test jersey slip since, now one of five players to have featured in every game for the Blues since Brad Fittler took over.

And again his ability to find space around the ruck set to be crucial at a fast Suncorp Stadium on Wednesday night.

"I would like to think me being there brought out the best in him, because I was there and he was competing with me," Farah said.

"At the time I remember everyone thought there was a rivalry between me and Cooky.

"But it never felt like that. I was there to help him and he asked plenty of questions.

"I think probably my presence opened his eyes to a few things and drove him to want to get that spot in front of me.

"Competition can bring the best out in him."

Australian Associated Press