Johnny Murtagh had the four-year-old, trained by Aidan O'Brien, handy throughout and he stayed on stoutly to beat the filly Sariska, with High Heeled in third.
Irish Derby winner Fame and Glory, a 5-6 favourite, benefited from the pacemaking of stablemate Dixie Music, which may have blunted the finishing speed of last year's Oaks winner Sariska.
Officials said up to 10 tigers had been poached from Sariska in the past two years - the news greatly alarmed conservationists and the Indian government which has since set up a task force to protect the tiger.