Give And Take claimed top honours in the Tattersalls Musidora Stakes at York and was cut to 16/1 from 40s for the Investec Oaks by Sky Bet.
A field of seven runners went to post for this recognised trial for next month's Classic at Epsom, with Highgarden the 5-2 favourite to provide trainer John Gosden with a fourth successive win in the race - and a sixth in eight years.
Frankie Dettori took the market leader to the lead from the start, but she was a spent force entering the final furlong, whereas the William Haggas-trained Give And Take (7-2) battled it out with Dancing Brave Bear on the stands' rail.
Ridden by James Doyle, Give And Take asserted close home to secure victory by a length.
Doyle said: "I was pleased with her. Each time she's ran to a creditable level. It took her a while to adapt to it but I was very pleased with here at the line. She gets the trip very well."
Haggas added: "I was delighted with her. She's a stakes winner for the breeder. I've never been convinced a mile and a half is her go. Nicholas Jones (owner-breeder) assures me she's from a good staying family, but she has always shown me speed at home.
"I have her in the Prix Saint-Alary next week (at Longchamp). I'm going to look at that. I know it's quite soon, but I'm not convinced about the Oaks. There is only one Oaks. If Mr Jones wants to go for it, then we will.
"I wasn't expecting James to ride him like that, just because we knew she'd be a strong stayer, but I left it up to him. I don't know about Epsom, I'll have to talk to her owner/breeder. He's adamant she'll stay further and I'm not so sure.
"She was a bit exposed by Sir Michael Stoute's filly (Crystal Hope) at Sandown, but we did have a penalty, and now we've won a Group Three. I know Ed (Vaughan) likes his filly and they looked a nice bunch in the paddock.
Sky Bet Racing PR Manager Michael Shinners said: "The Musidora is always a good trial and while the winner is a 16/1 chance for the Investec Oaks, she's not without a chance in an open year."