The 5-year-old mare rallied from last after a poor start and fought off Gio Ponti in the stretch to win by a length at Santa Anita, beating a loaded field of 11 males and becoming the first female to win the Classic in its 26-year history.

"There are tears coming to my eyes. I can't believe it," said trainer John Shirreffs, who eschewed a box seat to watch his star horse from the rail near the finish line.

Quality Road was scratched at the starting gate after he acted up and scraped his hind leg, delaying the start by several minutes. Zenyatta initially turned sideways when it was time to enter the gate, and all the commotion may have explained her poor start.

She broke on the wrong foot and dropped well behind the field, and hall of fame jockey Mike Smith let Zenyatta lope along near the back - her usual style in the early going.

"At the half-mile pole, I thought, 'Oh God, they're stacked up. There's no way I'm going to get around all these horses,' " Smith said.

Rounding the final turn, Zenyatta still had a lot of ground to make up on the leaders, and her chances appeared bleak.

"If she wins this, she'll be a super horse," announcer Trevor Denman shouted in his call.

Zenyatta then made a bold inside move midway through the far turn, and Smith angled her to the far outside as the crowd of 58,845 fans erupted.

Showing the grit of an undefeated champion, Zenyatta closed relentlessly and denied Gio Ponti the upset. Smith pumped his left arm as Zenyatta galloped past the grandstand for possibly the last time in her sterling career.

Owners Jerry and Ann Moss said Zenyatta, named after the 1980 album Zenyattà Mondata by the Police, likely will go to the breeding shed next year.

"I think she deserves to go out now with her record intact," Jerry Moss said.

Zenyatta ran 11/4 miles in 2 minutes, 0.62 seconds and paid $7.60, $5.60, and $3.80 as the 5-2 favorite.

"She's sent from heaven," said Smith, who lovingly patted Zenyatta's mane on the way to the gate. "She's incredible. I still didn't hit all gears."

Gio Ponti returned $9.20 and $6.60, while Britain-bred Twice Over paid $7 to show.

"The horse ran a great race, but he couldn't beat the winner," said Christophe Clement, who trains Gio Ponti. "She's a freak. What can I say?"

More than $1 million was bet to win on both Zenyatta and 3-1 second choice Rip Van Winkle, an Irish import who finished 10th.

Belmont Stakes winner Summer Bird was fourth and Kentucky Derby winner Mine That Bird ninth, extending his losing streak to five straight since his 50-1 upset on the first Saturday in May.

Zenyatta's presence gave a big boost to the signature event of the two-day world championships, which were missing the year's other star female, Rachel Alexandra.

The 3-year-old filly went 8 for 8 this year, including three wins against the boys, one coming in the Preakness Stakes. But Rachel Alexandra's owner, Jess Jackson, shut her down for the season rather than run her on the synthetic surface, which he dislikes.

Colonel John was fifth, followed by Richard's Kid, Awesome Gem, Regal Ransom, Mine That Bird, Rip Van Winkle, Einstein, and Girolamo.

American horses earned eight victories over the two-day championships, with Europe-based horses winning six, one better than last year's total.

Irish import Goldikova successfully defended her title in the $2 million Mile against 10 male rivals. Another Irish horse, Conduit, repeated in the $3 million Turf, and Pounced won the $1 million Juvenile Turf.

Three geldings won races - California Flag in the $1 million Turf Sprint; Dancing in Silks in the $2 million Sprint; and Furthest Land in the $1 million Dirt Mile.

Vale of York, part of Godolphin Racing's European division, won the $2 million Juvenile.