Ashton survived 11 match darts across the final two legs to triumph in a gripping finale, after Sherrock had fought back from 2-0 and 4-3 adrift to seize control of the contest.
Sherrock celebrated victory in the inaugural Women’s World Matchplay in 2022, but it was Ashton who came out on top on a memorable afternoon at the Empress Ballroom.
The Lancashire icon also saw off Robyn Byrne and reigning champion Beau Greaves on her way to glory, before sneaking past Sherrock to etch her name into Women’s World Matchplay history.
Ashton ran out a 4-2 winner against Irish star Byrne in the last eight, before halting Greaves’ bid for a third consecutive title with a terrific 5-3 victory – aided by a magnificent 140 checkout in leg four.
Sherrock defied a blistering start from Ashton to establish a 3-2 buffer, following up a 13-dart hold with a 14-darter and an 86 combination to take control of the tie.
Ashton – who landed 85 and 68 checkouts in the opening exchanges – regained the initiative with a 72 finish on tops to lead 4-3, only for Sherrock to win back-to-back legs to move to the cusp of glory at 5-4.
However, Sherrock then squandered eight match darts in a dramatic penultimate leg, before spurning a further three title darts in the decider.
Ashton fired in a timely maximum to set up a match-winning opportunity, and she took advantage of this reprieve, converting a two-dart 64 finish to seal the deal with a 14-darter.
Sherrock was aiming to join Greaves in becoming a multiple Women’s World Matchplay champion, although she was forced to settle for the runner-up trophy for a second straight year.
Sherrock opened her campaign with a 4-3 win over Gemma Hayter, fending off a brilliant fightback from the big stage debutant, who trailed 3-0 at one stage.
The 31-year-old then won through a gruelling nine-leg affair against Dutch star Van Leuven, who produced a brilliant 116 finish to force a deciding-leg shoot-out.
Van Leuven later squandered match darts to topple Sherrock, having dispatched Lorraine Winstanley in four legs to register her first victory on the Women’s World Matchplay stage.
The afternoon’s other quarter-final saw top seed Greaves average north of 96 in a 4-1 thumping of Finland’s Kirsi Viinikainen, which marked her seventh successive win at the Women's World Matchplay.
However, the premier player in the women’s game was punished for a profligate display against Ashton, despite crashing in four 180s throughout the contest.
Betfred Women's World Matchplay
QUARTER-FINALS
Beau Greaves 4-1 Kirsi Viinikainen
Lisa Ashton 4-2 Robyn Byrne
Noa-Lynn van Leuven 4-0 Lorraine Winstanley
Fallon Sherrock 4-3 Gemma Hayter
SEMI-FINALS
Lisa Ashton 5-3 Beau Greaves
Fallon Sherrock 5-4 Noa-Lynn van Leuven
FINAL
Lisa Ashton 6-5 Fallon Sherrock