Winter won a 1,000 Guineas during Newmarket to give tutor Aidan O’Brien a third double in a Guineas.
O’Brien won Saturday’s 2,000 Guineas with Churchill and also won both Classics in 2005 and 2012.
Winter, ridden by Wayne Lordan, denied Ryan Moore a Guineas double as stablemate and 9-4 favourite Rhododendron was second, with Frankie Dettori third on Daban.
O’Brien now has 4 wins in a competition and 27 British Classics wins.
The Irish trainer, who has won 13 of a final 27 British Classics, fielded 3 runners in a bid to win a fillies’ Classic, with Hydrangea his other runner.
While Rhododendron endured a uneasy passage, Winter stayed out of difficulty far-reaching of a field.
Lordan guided a 9-1 shot to a front entering a final furlong and hold off a plea of Rhododendron, who came home strongly.
“She trafficked utterly well,” pronounced Lordan. “I went brazen utterly early since she’s a filly that gallops and we knew a lane would fit her.
“This means a lot. I’m really beholden to Aidan for vouchsafing me keep a float on a filly.”