Odds-on favourite Islington won the Aston Upthorpe Yorkshire Oaks for the second year in a row.
Ridden by Kieren Fallon, the Sir Michael Stoute-trained four-year-old set sail for home just over two furlongs out, taking over from long-time leader L'Ancresse.
Although chased hard by Ocean Silk, Islington held on and eventually won by a length.
As usual, the four-year-old sweated up badly before the 1m 4f Group One race but it did not affect her performance as she came home to claim the £145,000 first prize.
Stoute confirmed afterwards that Islington would now be aimed at either the Champion Stakes at Newmarket or the Prix de l'Arc de Triomphe before tackling the Japan Cup.
The win marked a good start to the second day of the Ebor meeting for Stoute and Fallon, who also won the first race with the Aga Khan-owned Akshar.
Balmont won an exciting battle with Fokine to land a big gamble in the Scottish Equitable Gimcrack Stakes.
The two-year-old, trained by Jeremy Noseda, just edged home in the six-furlong Group Two contest to give Pat Eddery victory in his last Ebor meeting before he retires.
Byron, ridden by Frankie Dettori, finished third but was disqualified after a stewards' inquiry because of interference two furlongs out, with Grand Reward promoted into the place.
Dettori was also banned for three days for careless riding.
Aston Upthorpe Yorkshire Oaks (Group One)
1 Islington (K Fallon) 8-11f
2 Ocean Silk (J Fortune) 18-1
3 Summitville (M Fenton) 25-1
8 ran. Dist: 1l, 2l
Scottish Equitable Gimcrack Stakes (Group Two)
1 Balmont (Pat Eddery) 7-2
2 Fokine (M Hills) 9-1
3 Grand Reward (M Kinane) 7-4f
9 ran. Dist: Hd, 1¼l