Set to be named Victoria's leading jockey at season's end, Stackhouse guided the Ben and Jd Hayes-trained Mimi's Award to victory in the Deane Lester Flemington Cup (2800m) on Saturday.
Lester, a leading form analyst in Victoria who died earlier in the year, was instrumental in the resurrection of the Flemington Cup back in 2020.
"It's a big thrill and a big honour to win this race named after Deane. He was a big part of racing and I'm just so happy to have won this race," Stackhouse said.
Proving the more solid stayer, Mimi's Award ($4.40) got the better of the $2 favourite Mostly Cloudy to score by a long head with Savvy Valentino ($61) a further four lengths away third.
Stackhouse said the race worked out perfectly as he followed Jye McNeil aboard the favourite.
"She switches off and gets into a beautiful rhythm," Stackhouse said.
"The tempo was a lot stronger than I thought it might have been and I just stalked Jye the whole way. He gave me a good cart into it, and I knew what I had underneath me. She's such a good little stayer and tries her heart out. She got her head in front and held them off the whole way."