Midday held off Pure Clan for a 1 1/4-length win. Pure Clan, under Garrett Gomez, was gaining ground rapidly at the end but too late.
Forever Together also made a late run to take third, another 1 1/4 lengths back. Visit, who set the early pace, finished fourth.
Midday, a British-bred, 3-year-old daughter of Oasis Dream, ran the 1 1/4 miles on firm turf in a quick 1:59.14 under Thomas Queally. Cecil Henry trains the filly for her owner/breeder, Juddmonte Farms.
Starting in a well-matched field of eight, Midday paid $6.60 to win.
Midday came into the Breeders' Cup off a close third-place finish in the Prix de l'Opera at Longchamp in Paris last month. She now has three wins, two seconds and two third from seven starts this year, all of the others coming in England.