It was the second-straight Ballyroan Stakes success for Colin Keane, who partnered Vauban to victory last year.
That win sealed a trip to Australia for Vauban, who finished 14th as $5.50 favourite in last year's Melbourne Cup.
Vauban, like Crystal Black, won at Royal Ascot the start before the Ballyroan Stakes and Keane said his progression is why they are not putting any ceiling on the six-year-old.
"From 77 (official rating) to a Group 3, that's some horse," Keane said.
"We thought he'd be a solid handicapper to be honest and, with luck, going jumping because he's such a big horse." - Gerard Keane
"When he started winning, that ruled out jumping in case something ended up happening to him and he probably won't now."
Crystal Black now owns a place on the second line of Melbourne Cup betting, which is headed by Sydney Cup winner Circle Of Fire.