Back in the Sharks' pre-season Nikora committed the ultimate sin for an NRL player when he failed to turn up to training on time.

But rather than get shouted at, receive a fine or get sent for laps of PointsBet Stadium, Fitzgibbon's response left a lasting impression.

"Fitzy just sent me home," the New Zealand international told AAP.

"You have this feeling that you know you've done something wrong.

"I think it makes you feel worse when he says it so nicely because he's pretty chilled about it and there's no screaming or yelling.

"I was the first one to turn up late - I got some stuff mixed up, I thought it was a recovery day but I missed the meeting beforehand.

"He was pretty good about it and I came back the next day and just ripped in."

It was a lesson well learnt for Nikora, who says he gained an understanding of Fitzgibbon's ruthlessness as he seeks to turn the Sharks from an inconsistent side into one which could compete for silverware.

Nikora is a working example of that. He burst into the NRL in 2019 but struggled to rediscover that blistering form until this year.

"I think throughout 2019 I was loving it and I was in cruise control after then," he said.

"But Fitzy has helped me do the little things right so when the big plays do come they are there for you.

"He has opened my eyes - I thought I knew a bit about footy until Fitzy came in."

Since Fitzgibbon's arrival at the club, Cronulla have been on an upward curve and finished second this season.

Were it not for a 93rd-minute golden-point field goal against North Queensland, the Sharks could be having the week off.

As it is, they will face Souths in a winner-takes all game on Saturday to set up a preliminary final with Penrith.

"We went into last week with a do-or-die attitude," Nikora said. "Our defence wasn't where we wanted it to be and we need to clean that up."

Australian Associated Press