Frankie Dettori rode Snowfall through the rain to win the Oaks at Epsom - his sixth victory in the race.
The Aidan O'Brien-trained horse won by a record 16 lengths, breaking the previous record of 12 lengths set by Sun Princess in 1983.
Mystery Angel finished second, ahead of winner's stablemate Divinely in third.
"I was afraid of Santa Barbara coming from behind, but when I saw some daylight she kicked on," Dettori, 50, told ITV Racing.
It was a 40th British Classic triumph for O'Brien, who trains Saturday's Derby favourite Bolshoi Ballet.
Earlier, Martin Dwyer rode Pyledriver to victory in the Coronation Cup.
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