The Roos looked to have clinched the see-sawing contest when five-eighth Chad Sharp cut through to score for a 20-16 lead in the 73rd minute. But the Rosellas refused to die.

In the final minute they shifted left to centre David Pangai, and using the most potent sidestep in the competition, he beat Wes Tillott to score the match-winner.

Pangai's try capped a high-intensity match where the lead changed on five occasions and three times in the final 12 minutes.

In recent weeks speculation has been rife about problems in the Wests camp.

But lock Sean Rudder said yesterday's fightback and jubilant celebration of Pangai's try was proof the Rosellas were committed to winning the premiership.

"There hasn't been problems, but obviously when you're not going as well as you want to be going there's always going to be a little bit of disunity, but as you see, as soon as the team is going well again everyone is in there cuddling," he said.

Wests showed a massive improvement in defence from their 26-point loss to Maitland two week ago, withstanding a wave of Wyong attack in the first half.

"We did a lot of work on our defence this week because we were so loose in the last month and we said we've got to get off the line and work together," Rudder said.

Many considered Wyong premiership favourites before the game, but now they must beat Cessnock to keep their title defence alive.

Roos hooker Mitch Williams said it was a gut-wrenching way to lose a semi-final.

"It's just one more tackle and we go through and they don't, but that's footy," Williams said.

"We've been close every time we've played and we've drawn, but in the end they just got on top.

"I think they keep getting us in 10-minute lapses."

Wyong scored first when centre Jamie Davis hit a hole at pace.