Thirroul fullback Sam Clune believes the experience of NRL veterans Nathan Fien and Jamie Feeney could prove the Butchers's trump card in the pressure-cooker of finals football.

Captain-coach Fien only retired from the NRL last year after 276 top-grade appearances, while Feeney was a mainstay of the Bulldogs NRL side throughout the early 2000s, racking up 132 games.

Add centre Brent Grose's 54 appearances for Souths and the Roosters and the tally rises to 462 games; dwarfing the respective tallies of the other three semi-final combatants including Helensburgh, who they face in Sunday's major semi-final at WIN Stadium.

The trio have noticeably lifted in the Butchers's run to the minor premiership and Clune said their experience inspires confidence in an otherwise youthful side.

"We've got a lot experience in our side. We've got Brent Grose, Fienzy and Jamie Feeney who've played a fair bit of NRL," Clune said.

"They've always got something really good to say in our huddles and at training. Brent Grose does [a] lot of talking and he's one of those players that really steps up when we need him.

"I think we've really stepped up in the big games this year. That's where we've really performed well, so hopefully that helps us coming into these finals where it's crucial.

"I know I look to them to draw some inspiration from. I definitely think that'll be a major factor in the finals when we need them."

While the Butchers look to the likes of Fien and Feeney to provide experience, they undoubtedly look to Clune to bring the X-factor.

The livewire fullback earned a Country jumper this year on the back of standout performances for Thirroul and Illawarra with 13 tries in 13 games for the Butchers.

He produced the match-winner in the Butchers's last-gasp 20-18 victory over Wests in the final round of the regular season and enters this year's finals as the form player of the competition.

"I definitely didn't expect the Country jumper, I didn't even expect the call up into the Illawarra side. I wasn't really worried about the representative stuff," Clune said.

"I've been really happy at Thirroul.

"It's been a breath of fresh air from the last couple of years where I've struggled with injuries and form and just been doubting myself."