Owners Jerry and Ann Moss could have taken the easy way out and had their unbeaten 5-year-old mare defend her title in Friday's Breeders' Cup Ladies Classic. She would have been an odds-on favorite to win and finish her career 14-for-14.

Trainer John Shirreffs wanted to make sure she was at her absolute best before he made the commitment. He now believes it.

Jockey Mike Smith has ridden some truly wonderful horses in his Hall of Fame career. Zenyatta, he said, is the best. And he wants her to be able to prove it on racing's biggest stage.

So, late Saturday afternoon, with $5 million on the line in the BC Classic, the last race of a 2-day, 14-race, $25.5 million extravaganza, played out at one of America's greatest sporting stages, Santa Anita Park, with the San Gabriels towering over the proceedings, Zenyatta will get her chance.

She will face the winners of this year's Kentucky Derby (Mine That Bird), Belmont Stakes, Travers and Jockey Club Gold Cup (all Summer Bird), Santa Anita Handicap (Einstein), Florida Derby (Quality Road), Pacific Classic (Richard's Kid), Super Derby (Regal Ransom), as well as the winner of last year's Travers and Santa Anita Derby (Colonel John), America's best grass horse (Gio Ponti) and one of the best horses in Europe (Rip Van Winkle).

Zenyatta's amazing rally has brought her from last or near last to first in each of her starts. But those were just races against mostly ordinary horses. This is the race against an extraordinary group of horses.

The shadow of the amazing filly Rachel Alexandra looms over this Classic. Owner Jess Jackson kept her out of the BC because he objects to the synthetic surface at Santa Anita.

Regardless of how the Horse of the Year voting ends up, a Zenyatta win against males in the Classic would be a result for the ages.

"I've been blessed to be on some great horses," Smith said. "I've just never been on something that can turn it on like she does. She has a tremendous stride. It just seems to reach forever. It's almost an out-of-body feeling. I've almost got to where I'm a spectator myself on top of her with the best seat in the house. I'm just in awe of her."

And why not? Zenyatta will be the biggest horse in the field, towering over her male opponents. The enormous mare with the enormous stride runs like National Velvet. She comes from so far behind it is like there are two different races - the others' and Zenyatta's.

Even with the perfect record, there are detractors. Zenyatta has only raced outside of southern California once, has only raced on conventional dirt once.

One of the detractors is the man who trained Zenyatta's mother, Vertigineux.

"She's very overrated," said Michael Dickinson, now retired as a trainer and marketing his Tapeta racing surface around the world. "Been beating up on nothing. Tell me a good horse she has beaten. The other horse [Rachel] would destroy her.

"What's she beaten this year? Life and death to beat some horses you and I can't name. She's the most overrated thing."

Well, last year at Oaklawn Park, Zenyatta did crush Ginger Punch, the 2007 older female champion.

But that is the argument. Zenyatta has been handled carefully and her connections have taken few risks. That is no longer the argument. Everybody will now get to see.

The critics will have their argument confirmed. Or the true believers will get their coronation.

Vertigineux, Dickinson said, was meant to be a very good horse but, "Both her fetlocks were like grapefruits."

She was sent to Dickinson after she broke down because he was the patron saint of lost causes. He got her back to the races where she won a few times. She did not last.

Zenyatta has won every race. And she has lasted.

Win or lose, the Classic will be it.

"You just put a lump in my throat," Smith said when he was asked about the final race. "If we're blessed enough to win, I'm going to be so happy for all of us. But to see her go away, I get shook up about it."

Shirreffs trained 50-1 Giacomo to win the 2005 Kentucky Derby. That was a fluke, as Afleet Alex proved by trouncing Giacomo in the Preakness and Belmont Stakes.

Regardless of what she has been running against, Zenyatta is no fluke. Horses are not machines. She just runs like one.

"I'm always amazed at how well she performs," Shirreffs said. "She's like a stopper on a baseball team. When you're not doing so well or things are up against it, you bring out Zenyatta and you really feel good about it . . . She lifts the whole barn."

She often looks beaten, but never is. She looked absolutely beaten in the Aug. 9 Clement Hirsch at DelMar. She was just too far behind with too little time to get there. And then she got into gear.

How fast was she going in the final 100 yards that day? If she were racing Usain Bolt, she would have won by 40 yards.

"She crossed the wire that day going 40 miles per hour and she was just starting to hit her best stride," Smith said.

The dream race with Rachel won't happen.

"I would have loved it, let's just leave it at that," Smith said.

We won't get that, but we will get this.

Zenyatta has never run a really fast race. Which could be a product of her running style. Horses can run only so fast so the pace of the race really affects final times, especially for a horse coming from the back.

What Zenyatta does is run fast enough to pass all the horses in front of her.

"She does things that just ordinary horses can't do," Shirreffs said.

Unbeaten has a special cachet in sports. Almost inevitably, something goes wrong. So far, nothing has ever gone wrong with Zenyatta. Now, once and for all, everybody will get to see if she's as good as her record. *