Frankie Dettori won the Musidora Stakes at York on 18-1 outsider Soul Sister, a result that could see the two reunited for the Epsom Oaks in June.
The 52-year-old crossed the line four lengths clear of Novakai, with 15-8 favourite Infinite Cosmos in third.
Soul Sister is trained by John and Thady Gosden, who - with Dettori again in the saddle - won this race with Emily Upjohn 12 months ago.
"Frankie thinks she should run in the Oaks, so we will," John Gosden said.
Soul Sister, the daughter of Frankel, was a winner on debut at Doncaster in October but struggled in the Fred Darling when making her return to the track at Newbury last month.
But the three-year-old fared well in Wednesday's 10-furlong race, considered one of the best Oaks trials, powering clear in the final stages for a win that has seen her odds slashed for the Classic on 2 June, a race Dettori has won six times.
"Recently she's really come to herself, a lot of fillies have struggled this year with the cold and wet spring. She's really bloomed in her coat and shown her class today," Gosden added.
"Frankie is having a good spell, he was in Belmont last week. It looks like he has a chance in the Oaks and the Derby is quite open."
Dettori added: "She gave me a great feel, travelled well, quickened twice and won by four lengths. I wasn't really expecting that!"