A Duncan Young conversion bouncing through off the upright after a try - somehow, miraculously - was scored at the bottom of a mass of Lions and Roos players on the try line.

The Roos were slow to start in Sunday's all important fixture, with errors costing them on the scoreboard early and setting an ugly tone for the first half.

Three successive penalty goals slotted through the uprights by Orange City gun Keegan Harding came back to haunt the hosts, although an early, gritty try by Will Archer and a perfectly placed penalty kick from Hamish Gordon kept the hosts in the fight in the early goings.

Orange City's Steven Widders was again at his offensive best for the visitors, crossing for a try that further pushed the scoreboard in the Lions favour before halftime.

The result means the Lions will now be one half of an all-Orange grand final, a result that seemed all but impossible just a year ago and delighted City coach Viv Paasi.

"How good is that?" Paasi said.

"One thing I do know is that when both Orange sides are going well, the town's going well, I can't wait for the boys to get their chance at home, they're very keen and I'm incredibly proud of the way we stuck in the fight today."

While the penalty count read against Dubbo, Paasi felt the emotions had got the better of both sides at times, pointing out that a yellow card to Orange's Keith Lawson early in the second half had given Dubbo opportunity to score.

"There was a couple of yellows either way, I think the discipline wasn't great for both sides at times, but it was fitting of a final, both sides really wanted to win and that's what happens sometimes," Paasi said.

"They're a great side and a great club, we love playing them because they're such good hosts, I thought we both put in effort fitting of a grand final."

Lawson's absence from the field gave the Roos some room to score, with Johnny Mafiti, Jake Styles and Tim Beach combining to send Beach crashing over to draw the scores to 15 - 14.

Orange lost Keegan Harding to injury and the Roos' Tim Beach was sent off with a yellow shortly after, with Duncan Young slotting the penalty to launch the Lions back in front.

A penalty goal for Gordon bounced in off the post and handed the lead back in the game's fiery second half, with Tim Beach, Filisione Pauta and Shaun McHugh carrying the ball the length of the field and bouncing it back and forth between them to give McHugh a try of the year contender.

The 23-17 scoreline seemed insurmountable but a knock-on near the Roos line gave Orange the chance to muscle over in a tangle of limbs for their final try of the game.

Apex Oval waited with bated breath for the resulting conversion, which Duncan Young ricocheted in off the post to book the Lions a grand final berth with a 24 - 23 score.

While Roos skipper McHugh was disappointed to lose out on the Roos chance at revenge against the Emus, he was impressed by the growth shown by City.

"I think that's the beauty of this tight, small competition this year, you play each other twice and everyone gets a crack, everybody's given it their all this year," McHugh said.

"Best of luck to them, we wish we were there, but unfortunately it didn't go our way, but we'll be there supporting our girls and our second grade."

While Roos skipper Shaun McHugh was devastated to lose out on the opportunity to travel to Orange and battle the Emus one last time this year, he remained proud of the effort his side showed to come back from an 8 - 14 scoreline at halftime and an early onslaught of errors.

"Those penalties in our own half in that first half, we had three penalties down there and that's nine points gone straight away, if we hadn't made those little, silly mistakes it could have been different," McHugh said.