Thirroul fullback Sam Clune's rise from stop-gap utility to Country Firsts selection was a surprise to many, but certainly not to Butchers' coach Nathan Fien.

Not selected in Illawarra's original squad for this year's Country Championships, Clune was a late call-up for his ability to cover several positions.

He proved the championship winning side's X-factor off the bench, laying on crucial tries from dummy-half in both of Illawarra's matches, earning a bench spot on Thirroul teammate Jamie Feeney's Country Firsts side to tour Hawaii next month.

While he'll be without his fullback for two weeks during the tour, Fien said there was no player more deserving of the opportunity than the versatile Clune.

"Cluney's been outstanding all year. From the first day he rocked up to preseason he was head and shoulders above everyone in terms of his fitness," Fien said.

"He's a dedicated bloke and a competitor and it's just rewards for the way he's applied himself this year."

Clune has mostly worn the No 1 for the Butchers this season but Fien said his prowess out of dummy half for Illawarra had given him food for thought, with regular rake Joel Johnson spending most of the last month with the Illawarra Cutters.

"It was good to hear that he went really well in those Country Championships and played a few different roles," Fien said.

"He came on as hooker, which has opened my eyes a bit.

"We've got Joely there but he [Clune] could play in that position going into the back end of the year."

Clune will wear his regular No 1 against Wests this Sunday in a match shaping as a grudge match following the two side's fiery encounter when they last met at Gibson Park.

The Butchers ground out a tough 26-20 victory on that occasion but most of the attention post-match was on two all-in brawls that erupted during the match.

Fien doesn't expect the same fireworks in the return clash this week but with a top two spot on the line he's certain it will be a great spectacle.

"The round one game was a great game of footy. The intensity was definitely there and I don't see that being any different," Fien said.

"It's second versus third and it's the last game of the third round so for us it's quite big.

"If we can get them on Sunday we'll be three points clear of them [in second] going into the final round."