The 19-year-old had the rolling South Sydney pack running at him for 80 minutes in Saturday's golden-point epic but stood up to show he can hold his own against the big boys.

After starring in the NSW Cup this year Simpkin was called into the NRL side this week at the expense of dropped dummy-half Jacob Liddle.

And despite the Rabbitohs snatching an 18-14 win at Stadium Australia, Simpkin took almost double the number of runs as opposing hooker Damien Cook.

He gave spark out of dummy-half, all but ensuring his place in the side against Manly next Sunday.

"For his first game, 80 minutes, he had some fairly large blokes running at him and he handled it really well," coach Michael Maguire said.

"He rolled the ruck really well at times.

"He'll grow off the back of that and the combinations with our spine."

Tigers halfback Luke Brooks also had praise for the young dummy-half who played just one game of rugby league last year due to COVID-19.

He's the leading try-scorer in NSW Cup this season with six from five games and tops the tackle count with 213.

"It was a tough effort for him to play the full 80," Brooks said.

"He's been playing some good footy in Cup and I was really happy with his performance. He was good in defence.

"He's a pretty strong boy so he can handle his defence but that was the most pleasing thing for him."

Although the Tigers were heartbroken with the loss, the change in defensive mindset was a huge win for the struggling club.

It was the first time in 15 games they had kept an opponent to less than 20 points.

"It's just pure attitude and that attitude is what we have to bring week in and week out as a group and that will grow our success and where we need to take this team," Maguire said.

"If we continually work in that space and play with that standard then those games will roll our way and that's what we need to work towards."

Australian Associated Press