York, a new side put together this season by their director of rugby Lindsay Anfield, shocked 2018 Super League champions Wigan Warriors and the following year’s table toppers Castleford Tigers to reach Saturday’s final at Leigh.
Predictably, Saints proved too strong on the big occasion, running in seven tries to York’s one, but Knights gave a better account of themselves than the 34-6 scoreline suggests.
Saints - whose second-rower Emily Rudge was named player of the match - were more cohesive as a unit, but the real difference was their clinical finishing.
They were ruthless in York territory, while the runners up failed to turn some heavy pressure into points.
Both teams were in their first final, but York had the big-game experience courtesy of the five England players they signed from Castleford at the start of the campaign.
That showed early on as York made the better start, almost going ahead when Rhiannion Marshall crashed over, but she was held up by Chantelle Crowl.
But once they had survived the early onslaught, Saints began to create opportunities of their own and four tries fired them into a commanding 20-0 lead at the break.
After 14 minutes of York attacks, Saints scored with their first chance when an unmarked Danielle Bush was given a walk-in from Faye Gaskin’s long ball over the top of the defence.
Five minutes later, the Super League leaders doubled their advantage through a terrific finish at the corner by Rachael Woosey, off Rebecca Rotheram’s pass.
Saints knocked on from the restart after both tries, but York failed to take advantage, though Sinead Peach was held up over the line and two tries in four minutes, both created by Jodie Cunningham and converted by Stott, took the game away from them.
Eight minutes before the break Cunningham’s short pass sent Rudge into a gap and she rounded the full-back before holding off Kirsty Gentles’ last-gasp tackle.
This time York got the ball back from Marshall’s clever short kick-off, but Katie Langan was tackled in possession on the last and in the set from the turnover, Cunningham sent Amy Hardcastle dashing away from deep inside Saints territory.
York were rewarded for their efforts seven minutes into the second half, after some heavy pressure, when Peach dabbed a grubber behind Saints’ line, Rotheram failed to tidy up and the Knights hooker ran through to touch down for a try which Marshall converted.
That gave York a glimmer, but moments later Marshall kicked straight at Rudge who counter-attacked and though she was chased down by York’s full-back Emma Hardy, Hardcastle sent Woosey in for Saints’ fifth try in the same set; then moments later Carrie Roberts finished brilliantly from Rotheram’s pass and though neither try was converted, Knights had no way back from 28-6 down.
Paige Travis stepped through and managed to hold off Gentles for a try which Stott improved to complete the scoring, 12 minutes from time.
In what could be a blow to England’s World Cup hopes, Saints lost half-back Faye Gaskin to injury after she had set up their opening try.
She left the ground on crutches, with her right knee in a brace.