Ivan Cleary has backed suggestions to play the World Club Challenge in Las Vegas as the curtain comes down on the NRL's second annual visit to the United States.

A total of 45,209 fans attended Allegiant Stadium for the four games on Sunday (AEDT), with Cleary's Penrith edging Cronulla out for a 28-22 NRL win in the last of those.

The Vegas experiment was bigger and bolder in 2025; twice the number of fixtures were on the program and more punters turned out to events in Vegas in the lead-up.

But the fluctuating crowd on Sunday is likely to come under focus as the NRL takes stock ahead of next year's third trip.

Fans are not permitted to re-enter Allegiant Stadium after leaving and the crowd was noticeably thinner by the fourth game between the Panthers and Sharks.

Punters who arrived for the first game and left after the fourth were at the stadium for a potentially-unpalatable nine hours.

It is difficult to see the women's fixture being cut, or a Super League presence being scrapped entirely given an estimated 10,000 fans travelled over for Wigan's 48-24 thrashing of Warrington.

Spreading the games across two days would also come with greater financial burden as the NRL fights to even cover the cost of this year's edition.

If the NRL determines four matches is too long, the league could consider playing one NRL game, a women's match and the World Club Challenge.

The World Club Challenge was unable to go ahead this year, with the Panthers and Wigan both participating in the Vegas weekend and unable to find an alternate time.

Rhodri Jones, managing director of Rugby League Commerical, has been among those to suggest playing the clash of NRL and Super League champions in Vegas.

"I honestly think we should," said four-time premiership coach Cleary.

"It's a shame that that game didn't happen (in 2025) and you saw how well Wigan played today as well.

"They are a juggernaut at the moment. It's probably good we didn't play them, actually.

"I think it's a really good concept. We didn't have to go last year but we really wanted to."

Cleary's Panthers travelled to England to face Wigan in last year's World Club Challenge, which the club has never won despite its four consecutive premiership triumphs.

"Even though we lost, it was a really good experience," Cleary said.

"It probably helped us for this week, to be honest. I definitely think that's a part of rugby league that needs to survive."

Attention has already turned to which NRL clubs will be included in next year's Las Vegas visit.

St George Illawarra, Canterbury, Newcastle and North Queensland have all indicated their interest, with Cleary urging his rival coaches to put their hands up.

"I would say to any of the teams thinking about whether they should come, they should definitely come," he said.

"It is an honour, actually, to be able to come here and be a part of something so special."