The Nant Conwy team looked as though they were going to be crowned champions when Nel Metcalfe kicked her side into a one point lead with a penalty in the last minute, but back came the Quins to pull off a mighty finish through Wales U18 cap Bellamy.
The Gogs got off to the better start and their early pressure led to a try from Erin Evans, who bundled her way over the line ahead of the flailing Quins forwards.
However, a piece of ingenuity from Quins star Mya Dixon in quickly taking a penalty and passing on to Georgia Morgan caught Ceirw by surprise. Morgan drove through a sea of bodies to level the scores as both tries remained unconverted.
Quins piled forward, and very nearly took the lead, but Gwennan Hopkins failed to ground the ball after crossing the line. Then Morgan twisted and turning past the Ceirw backs before setting up Gabby Healan to take the plaudits with a try that Dixon improved.
Another quickly taken penalty earned another try, this time for the trailing side. Ceirw’s hooker Ffion Williams benefitted, but Gwenllian Hughes missed the conversion to leave them two points adrift.
Morgan was again influential for Quins as they extended their lead just before half-time. She battled through three tackles to claim her second try. Dixon’s conversion made it 19-10 at the break to the Cardiff club.
Ceirw needed to start quickly in the second half, which they did. Evans grabbed her second try after latching onto a magical offload from the impressive Metcalfe.
But Quins continued to fight back every time Ceirw challenged them. Bellamy charged forward into acres of space and sent Healan racing over for her second try to extend the lead to nine points.
Quins lost Dixon to the sin-bin and they continued to concede penalties as their discipline became an issue, especially at the set-pice. This led to Metcalfe scoring and converting her own try, making it a two point game going into the final 10 minutes.
In the closing minute of the game another penalty to Ceirw gave Metcalfe the chance to shoot for glory and her successful kick edged the north Walians into a 25-24 lead. The cup looked destined for a long trek north, but there was just enough time for one last roll of the dice.
Somehow the Quins managed to work the ball into the hands of Bellamy and she dived to score the try that sent her fans into raptures and finally slam the door shut on a spectacular effort from Ceirw.