Manchester Thunder were beaten for the first time this season as Hertfordshire Mavericks booked a Superleague final meeting with Surrey Storm.
Defending champions Thunder finished top of the table and played their semi-final in front of a club-record 4,000 fans at the Manchester Arena.
But Tracey Neville's side lost 48-41 after a dominant Mavericks display.
Surrey made the final for the third time in four seasons with a 76-60 win over Yorkshire Jets.
Now in its 10th season, the English domestic Superleague is made up of eight semi-professional franchises, with the top four progressing to the play-offs.
First-time semi-finalists Yorkshire Jets finished third in the table, one place behind Surrey, and led by two points at half-time at half time in Saturday's first semi-final.
But Storm pulled ahead to secure an emphatic home win.
Everything pointed to a replay of last year's final but Thunder were to be denied.
Two-time title winners Hertfordshire, who finished fourth at the end of the regular season, took the first quarter by two points and led by the same margin at half-time, thanks to a solid defensive display from Naida Hutchinson and Layla Guscoth.
Thunder fought back in the third quarter, helped by the introduction of Jodie Gibson at goal defence, and went in level at 35-35.
But the Mavericks capitalised on handling errors from the hosts, for whom shooter Helen Housby missed chances, and pulled ahead to secure victory.