Zenyatta came from last to first to justify odds-on favouritism in the Breeders' Cup Ladies' Classic.
The American superfilly lived up to her huge reputation by landing odds of 1-2 in the finale to Friday's card at Santa Anita.
She made it nine wins from nine starts by comfortably outpointing Cocoa Beach (7-1) and Music Note (9-1) to come home in front.
Jockey Mike Smith allowed Zenyatta to bring up the rear in the early stages, around 10 lengths off the pace.
And it wasn't until the field began the turn out of the back stretch that he shook the reins and asked her to improve.
The response was instant and she cruised round the entire field to take it up down the stretch.
Once in front she didn't run away from her rivals, but never looked in danger and kept on well to score with ease.
The victory completed a double for Smith on Friday night after he took the Juvenile Fillies on the brilliant Stardom Bound.
"I'm in awe - I've never seen anything like it," said the winning jockey.
"She just does what she does, she's just amazing."
Winning trainer John Shirreffs added: "We just can't believe it. She just makes thing happen. She is special and we are blessed to have her.
"From the minute she started racing she showed a dimension you would never expect."