Mildenberger made stamina count in the bet365 Feilden Stakes at Newmarket.
Fortune’s Pearl blazed a trail for much of the contest and was still in a commanding lead entering the Dip.
However, Mildenberger began to make progress under James Doyle as he met the rising ground and ate into the lead.
At the line, Mark Johnston’s colt was half a length to the good, with Kew Gardens a disappointing six lengths away in third.
The winning trainer said: “James said he wasn’t sure if they’d gone quick enough and he was laid back early on, he wasn’t sure if he’d have gone the pace if they were going any faster.
“I thought he’d given the leader too much of a start but he’s got to him well in the end, looks as though he’ll stay every inch of the trip at least, which we always thought would be the case.
“The Dante’s the obvious next step. Like we said with Permian last year you go to the Dante and it tells you whether you are going to the Derby or not.
“I suppose he is [a similar type to Permian]. We’d not thought about it. Permian started in a handicap, albeit it turned out to be a very good handicap. He hadn’t been as consistent as this fellow was as a two-year-old.
“He can get quite worked up beforehand, he wears a lip chain in the preliminaries but he has a great attitude once he gets out on the course.”
Purser meanwhile, got back to winning ways in the British EBF bet365 Conditions Stakes.
The raced developed into a duel with Symbolization from some way out, but the race-fit Purser stayed on strongly under Frankie Dettori to score by a neck.
It was ten lengths back to Stormbringer in third.
“It was great, the horse showed a lot of courage giving three pounds to the second. He’s not easy to place. We’ll come back here for the King Charles II and the Jersey would be another obvious place,” winning trainer John Gosden told Racing UK.