Sixteen-year-old winger Fran Goldthorp scored two second half tries as Leeds Rhinos Women completed a cup final double.
Adam Cuthbertson’s side had edged out the Tigers in the Challenge Cup in July, and recovered from a shaky start to add the Super League title. Goldthorp - who also touched down in that win - scored twice in the space of nine second half minutes.
The Rhinos also had a influential performance from recently crowned Women of Steel Courtney Hill at scrum-half, with the Australian creating two tries.
Cuthbertson said: "There’s so much character from the girls. They’ve got this unbelievable ability to never give up - that shone through in that second half.
"I’m so glad for them, they’ve worked so hard for this and deserve every bit of it."
On the performance of Goldthorp, Cuthbertson added: “She’s something else. She’s come in midway through the season and is an absolute natural talent. She’s got that athleticism that you can’t coach.
"She took her moment tonight and really shone. She’s definitely one we’re going to have to keep an eye on as a rugby league community because she’s brilliant at everything - she’s brilliant at rugby union and a great cricketer.
"We need to make sure we keep her in the game because when she puts on displays like that tonight she’s a joy to watch. We need people coming to watch players like that to grow the game going forward."
Defeat provided a disappointing end to the season for a Castleford side that lost just once in the league but missed out in both finals.
The Tigers had threatened to run away with the game early on with two tries inside the first six minutes. Tara Stanley and Lucy Eastwood combined for winger Maisie Lumb to finish in the corner, before Rhiannon Marshall’s outstanding pass put Lacey Owen over.
But the Rhinos gradually gained a foothold in the game. They hit back before half-time as Abby Eatock showed superb pace to beat Stanley on the outside, and were level when the increasingly prominent Hill created a try for Goldthorp.
Then the winger produced a moment of magic, breaking from dummy half 60 metres out, stepping inside Stanley and racing to the line.
But there was controversy in the score too, with replays indicating Goldthorp may not have grounded the ball in Hollie Dodd’s desperate cover tackle.
Hill’s conversion made it 14-8 and the scrum-half then turned creator again to send Elle Frain over for the decisive try.
Kelsey Gentles gave the Tigers hope of a late comeback with a late response, but the Rhinos stood firm.
Tigers coach Lindsay Anfield said: "The first 10 minutes they stuck to what we asked them to do. Fatigue set in a little bit and they just reverted back to type and started doing their own thing, which is really disappointing. Leeds do the basics treally well and I have no complaints."
