Exeter Chiefs came from behind in a thrilling semi-final to beat Bristol Bears 28-24 and reach a first Premier 15s final against Saracens.
Chiefs led for 73 minutes until Hannah West scored for Bears, but Jennine Detiveaux hit back with three minutes remaining at Sandy Park.
It followed a 30-10 victory for Saracens against defending champions Harlequins in the earlier semi-final.
Exeter will face Sarries in the final in Worcester on Friday, 3 June.
Chiefs narrowly edged past their south-west rivals by three points in the final league game of the season last weekend, and this last-four meeting was just as intense.
The hosts scored two early tries through Hope Rogers and Linde van der Velden, with both converted by Gabby Cantorna, as they dominated early on.
Rogers crashed over for her second to extend the advantage before West and Keira Bevan scored to reduce the deficit to nine points at the break.
The second half was a different story as Bears responded well. A Phoebe Murray try and an Amber Reed conversion brought the visitors to within two points.
West was the beneficiary to ground the ball at the back of the maul as Bears took the lead for the first time, with seven minutes remaining, but Chiefs hit back from the kick off and stormed down the other end as Detiveaux crashed over.
Speaking to BBC Sport, Exeter head coach Susie Appleby said she was "exhausted" after a "special" performance from her side.
"We found ourselves really dominant in the set piece for the first 20 minutes but then we need to express and open up," said Appleby. "We were going through multi-phase defence and then giving the ball up.
"There is no head dropping in this club, it is unbelievable and they are fighters. They will fight to the end and they always believe anything is possible, they are amazing to coach."
Saracens avenge final last season's defeat
Saracens cruised to victory over defending champions Harlequins to reach their fourth consecutive Premier 15s final.
Poppy Cleall scored two first-half tries and Marlie Packer also crossed as the hosts asserted their dominance.
Jess Breach reduced the deficit at the interval but May Campbell stretched Sarries' lead minutes after the break.
Despite Amy Cokayne's late consolation, Saracens will face Exeter Chiefs in the final.
Sarries were beaten in last year's final at Gloucester as Quins won their first title, but they made light work of the champions in the north London heat.
The early game nerves made for a disjointed start for both sides before Cleall picked up from the base of the ruck and powered over for the opening try.
Packer then showed her strength to spin out of the first tackle and smash her way over the line as Sarries blew Quins away with two tries in four minutes.
Alev Kelter's penalty nudged them further ahead before Quins rallied and hit back through Breach in the corner.
Player of the match Cleall restored Saracens' advantage with another powerful surge close to the line and the game was seemingly out of reach at half-time, with the score 22-5.
Campbell added a fourth try five minutes into the second half from a rolling maul straight off the training ground, with Cokayne's late try salvaging little more than pride for the visitors.
Speaking to BBC Sport, Cleall said the win was a "great reward for a tough season".
"Teams have pushed us this year and we got humiliated at Exeter, then got the win against Wasps coming into this game against the arch nemesis in Quins," said Cleall.
"It was awesome to have it at home with the fireworks and red smoke in front of this great crowd. It was awesome to get the win.
"We didn't play that well in the final last year at Gloucester but they cannot defend the title now and it will be a new winner.
"In the week, they were saying some things in the media about a new side playing in the final, and we used that as motivation as it wasn't going to be us."