The new rule in place specifically for the Cup gives coach's one challenge to a foul call provided they have a timeout in the bank. An unsuccessful challenge results in the loss of a timeout and, as such, is not expected to be used frivolously.

It was used to good effect by Cairns coach and star Mike Kelly and Scott Machado on Saturday night, turning a foul that would've sent Tyler Harvey to the line into a Cairns ball at the baseline. It also meant Machado was not forced to sit with his third personal foul, instead dropping three straight triples and orchestrating a comeback from 12 points down for an epic win.

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Harvey was also denied an and-one opportunity late in the game, with a Hawks challenge unsuccessful despite replays showing he had not dribbled between being fouled and putting up his successful shot.

Goorjian was also left frustrated in his side's win over the New Zealand on Monday when he was unable to challenge what replays showed was a blatant goal-tend through the net from Breakers big Finn Delaney. That was not up for challenge, but out-of-bounds calls are subject to endless reviews at the discretion of referees.

The six-time championship-winner is a huge fan of the Cup concept but, with all games counting towards the NBL season proper, says the league shouldn't be trialing new rules with full competition points on the line.

"We met as coaches and I don't think we're in favour of it to be honest with you," Goorjian said.

"This tournament's a great idea and everyone's supportive of the tournament. It's great to be here and have this and I hope it's ongoing... but these games count and are very important for our season and I don't think you should add or change rules for this tournament when this tournament applies to the regular season.

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"I found the coach's challenge really confusing. [The Breakers] had a clear goal-tend, you can't challenge that, I had no idea you couldn't. There's a lot of confusion there. I was involved in this a little bit in China and the coaches were worried about it.

"What happens is, it's going to decide games. I didn't want to say anything but in the Cairns game when Tyler went to the bucket [and was fouled] that [challenge] was a five-point swing and turned the game around. On the last one we asked and we lost that one and he didn't get the shots.

"Those are big, big plays and these games in this tournament are going to be tight. I'd like to stick with the rules we have during the regular season and not change them for this tournament because this tournament counts in the regular season and that's why we're all here, to make that [top] four."

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