Cook has pipped Farah for the Rabbitohs' No.9 jersey for Saturday's round-one NRL clash with the Warriors in Perth.

And with new Rabbitohs coach Anthony Seibold keen to keep the starting hooker on for entire games this season, Farah is facing a bleak year if he can't snare the starting spot back.

Farah isn't used to playing second fiddle, having starred in the NRL during the bulk of his 14-year stint at the Wests Tigers, earning call-ups to the NSW Origin and Australian sides.

But instead of sulking about his round-one demotion at Souths, Farah has taken the dumping in his stride.

"He's been very good. He's been very professional about it and very helpful at the same time," Cook said of Farah.

"Robbie and myself have always had that healthy battle.

"Over the past two weeks, since the trial, since we knew (I would be starting), he's been very helpful.

"Just after training today, he helped me go through some kicking and passing as well.

"He's still playing great footy.

"He's still putting that pressure on me to hold my spot. And that's what you want. It's going to bring the best out of both of us."

Cook has never been able to establish himself as the No.1 hooker during stints at St George Illawarra, Canterbury and Souths.

But he's determined to change that this season, and hopes it will lead to a NSW call-up.

"Origin is on every player's list and it's definitely on mine," Cook said.

"It would be a dream come true."

When South Sydney signed Farah ahead of last season, Cook wasn't sure what his future held.

But he knuckled down and vowed to learn as much as he could from Farah.

The determination has paid off in spades, but Cook knows he is only one bad performance away from potentially being dumped to the bench.

And Cook hosed down any doubts about whether he could play out entire games, saying he was fit enough to go the full 80 minutes.

Australian Associated Press