The Benalla product starred for the Cats in the gutsy 6.4 (40) to 5.3 (33) triumph over Southern Saints at GMHBA Stadium.
Webster, a member of the club's AFLW squad, recorded a classy 21-disposal and eight-tackle game that also involved a vital goal.
Mooroopna product Tamara Smith also provided valuable support in the semi-final victory.
The former NCWL premiership captain collected 11 touches and laid five tackles.
It was a brave come-from-behind win for the Cats.
Down by 11 points at the main break, Geelong booted five goals to three in the second half to produce a stunning comeback win.
The result means the pair of exports will meet Finley product Eloise Ashley-Cooper and her Essendon teammates this weekend.
The Bombers were unable to get over the line in the semi-final bout against Collingwood, suffering a tense seven-point defeat.
It was a low-scoring affair at Victoria Park, as the Pies saluted 2.6 (18) to 1.5 (11) to progress through to the grand final.
Ashley-Cooper was outstanding for the Bombers and was named in the best players for her 10-disposal and four-tackle game.
The preliminary final will be held at Windy Hill at noon.
In AFL ranks, talented Mooroopna product Clayton Oliver might be dubbed Charlie come September.
The skilled on-baller has taken his game to another level in 2021 and currently sits second on the afl.com.au Brownlow Medal predictor.
Oliver, an All-Australian and club best-and-fairest winner, is tipped to be on 23 votes after 17 rounds — three votes behind Western Bulldogs skipper Marcus Bontempelli.
The Melbourne star has averaged 30.9 disposals, 7.4 clearances and 5.2 tackles a game.
The Dees currently sit on top of the ladder.
Meanwhile, Seymour product David Mundy is another export from the region who is high on the Brownlow Medal predictor count.
The Fremantle stalwart is expected to have polled 18 votes already as he enjoys another sublime season at age 35.
Echuca's Ollie Wines is not far behind on the pecking order with 14 expected votes.
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