The 16 year-old Royal Fremantle Golf Club member and World Number 8 amateur defeated defending champion and World Number 2 Ariya Jutanugarn (Thailand), 2&1 in the semi final.
Southern California's Alison Lee, 17, eliminated World No. 1 New Zealander and Australian Amateur champion Lydia Ko, also by a 2&1 margin, in Friday's semifinal matches at the 6,291-yard (5,754 metre), par-72 layout.
For the first time in Match Play, Jutanugarn, 16, opened with a bogey at the par-4 first, giving Minjee Lee an immediate lead. Lee lost the second with a bogey to square the match, but capitalised on a Jutanugarn double-bogey 6 at the par-4 fourth to reclaim the lead.
It was a lead she never relinquished. Lee led 4-up by the 12th hole and had a short putt on the 13th to take the match to a 5-up lead. But her three-putt bogey at the par-5 14th allowed Jutanugarn the chance to fight back. "I probably lost my head somewhere in the clouds," Lee said.
A wayward tee shot from Lee at the par-3 15th gave Jutanugarn another breath of life and trimmed the lead to two. But Lee, who four amateur titles in 2011, steadied her game with pars at 16 and 17 to win the match and secure a spot in the final of her first USGA competition.
"I wasn't going to lose, not at that point." said Lee, a semifinalist at this year's Australian Amateur at Woodlands Golf Club in Melbourne. "Just a few loose holes. It's ok. I got the job done."
The final will begin on Saturday evening (AEST).