The five-year-old surged from the outside to break free from the eight-horse field down the stretch and win the year's richest race for fillies and mares.
Three-year-old Abel Tasman chased the Dallas Stewart-trained Forever Unbridled as the finish approached but could not close the gap in what amounted to a two-horse race on a chilly day at the oceanside racetrack.
"The whole key was I wanted to save ground on the first turn and I was able to do that," Forever Unbridled jockey John Velazquez told reporters.
"I got her in a comfortable position where I thought she was going well. At the three-eighths pole I followed Jose Ortiz's horse [Elate] and all of a sudden she stopped and I had to go a little sooner than I wanted to.
"I got to the lead a little too soon for me but, I mean, it was perfect."
In just her seventh career start, Paradise Woods came in third while favourite Elate finished fourth in the 1 1/8 mile (1.8 km) race.
Champagne Room took the lead early with Paradise Woods in hot pursuit.
But at the far turn, Velazquez kicked Forever Unbridled into high gear and took the lead for good despite the pressure applied by Abel Tasman.
"Down the stretch she tried hard and she ran her race," Abel Tasman trainer Bob Baffert said.
"She just got beat by a really good filly today," Baffert said of Charles Fipke-owned horse.
With the win, Forever Unbridled completed a perfect year with victories in the Fleur De Lis at Churchill Downs and the Personal Ensign at Saratoga as well as claiming her fourth Grade One win.
(Reporting by Rory Carroll, editing by Nick Mulvenney)
