ARCADIA, Calif. - The Breeders' Cup Ladies' Classic is missing its leading lady, with defending champion Zenyatta pitting her 13-0 record against the boys on the second day of the season-ending world championships.

Her defection leaves Music Note as the early 9-5 favorite in the eight-horse field for the 11/8-mile Ladies' Classic today at Santa Anita.

The $2 million race is the highlight of six Breeders' Cup races on Day One, five of them featuring females, with the $500,000 Marathon for males.

Zenyatta's presence in Saturday's $5 million Classic is daunting to some of her rivals.

"I would have entered her with the fillies so I didn't have to run at her," said Chip Woolley Jr., who trains Kentucky Derby winner Mine That Bird.

"You know she's going to be running late and she has a lot of style, much the same as my horse. She's twice his size, so if she decides to knock him out of the way, she's got a good chance."

Hall of Fame trainer Bob Baffert saddles long shot Richard's Kid in the Classic.

"I don't like to see her in there - I'm in there with her," he said. "But she's going to bring so much. Everybody is going to be watching with her in there. We need a big boost right now and she's going to be our boost."

Zenyatta is going against male competition for the first time in her career. She will break from the No. 4 post in the 11/4-mile race.

"Optimism is high," said Jerry Moss, who co-owns the 5-year-old mare with his wife. "I think everybody is in for a treat."

Zenyatta is grabbing the attention in the absence of Rachel Alexandra, who was 8-for-8 this year, including 3 wins over male horses.

Owner Jess Jackson shut her down for the season because he dislikes Santa Anita's synthetic track on which his two-time Horse of the Year Curlin faded to fourth in last year's Classic.

No female horse has won the Classic in its 25-year history.

Zenyatta will break from the No. 1 post and likely use her tactical speed to go to the lead.

"She's really not a nervous filly (like) people seem to think," Carroll said. "Any race that we've taken her to she's actually been good until the rider gets on her back. Once somebody gets on, she wants her things her way and she starts to perform."

Even without Zenyatta, trainer John Shirreffs still has a horse in the Ladies' Classic with Life is Sweet, who has fruitlessly chased Zenyatta in three of her last four races.

"It breaks my heart that Zenyatta is not in the race," owner Marty Wygod said, jokingly.

The $500,000 Marathon begins today's races, with gelding Cloudy's Knight making his Breeders' Cup debut at age 9.