The opens Vipers produced their "best game" of the season so far as they booked a ticket to the grand final.
Taking on the Wiradjuri Goannas in the Western Women's Rugby League 2v3 match-up, it was the home side who came out firing at Pride Park on Saturday.
The Vipers went into the half-time break up 22-10 and despite some nervous moments, ran away with things at the end to finish 42-22 victors.
Coach Ryan Prevett said the key to success was, as always, ball control.
"If we can control the ball, we'll compete with any team," he said.
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"There's been at least three games this season where we've been lucky to win and that was mainly due to lack of ball control.
"When we get our heads right and not push silly passes, we'll be right in there with a chance."
The first year Vipers coach pointed to Georgie Barrett, Lily Baker and Paige Selton as big factors for the win.
"We're peaking when it matters," he added.
The Vipers will now take on the powerhouse that is the Panorama Platypi who defeated Mudgee 34-18.
Kathryn Gullifer, who touched down for a try in the first half for the hosts, said it was an awesome feeling to book a spot in the opens decider.
"We've just got to put our heads down and have a good crack next week," the Platypi player said.
"Those Mudgee girls were solid. Some of us play them in union, so it was a good match."
Speedy fullback Tiana Anderson had two tries within the first six minutes, but Mudgee hit back through Alyssa Shoulders to trail 8-6.
Gullifer, Cheynoah Amone and Menzi White all crashed over before the break, while Mudgee's Emma Cornwell got one for the visitors, as Platypi took a 24-12 lead to the half-time break.
The game was played in hot conditions, in stark contrast to the forecast for Saturday's grand final, which is expected to bring rain and much cooler temperatures.
Gullifer said it was a tough battle on Sunday with the heat.
"It was horrible," she said.
"Getting up off the ground after contact and then with the heat, it just gave that extra bit of sting.
All five grades - under 12s, 14s, 16s, 18s and opens - will be played at Jack Arrow Oval on Saturday, November 25. Start times are yet to be announced.
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