A SUPERSTAR will grace the 26th Breeders' Cup at Santa Anita next weekend. Not Sea The Stars but Zenyatta, who is named after a Police album, trained by a former US Marine and has won all 13 of her races over the past three seasons, equalling a record set 20 years ago by the great Personal Ensign. If, as expected, connections confirm that the wondermare will take on the colts in the Classic rather than defend her title against her own sex in the Ladies' Classic, the five-year-old's 14th victory would make history on every count. No filly or mare has ever won the Classic, the richest race in the American calendar; but, as Sea The Stars proved in becoming the first horse to win the 2,000 Guineas, the Derby and the Arc, the past is there to be mocked. When Tom Robbins, one of American racing's shrewdest judges, heard last week that some British bookmakers were offering Zenyatta at 6-1 for the $5m Classic with Coolmore's Rip Van Winkle the strong favourite at 6-4, his bewilderment — even communicated down a telephone line from California — spoke volumes for the confidence invested in the imperious, unflappable, unbeaten mare. Have any of you guys seen Zenyatta in full flight?

Statistics alone do not make the giant-striding daughter of Street Cry a phenomenon. She races as if sired by Pegasus, dawdling through the first half of her races before launching a devastating burst of speed off the bend, picking off her rivals and easing down before the line. "She's sent from God, this horse, I tell you," said Mike Smith, her jockey, after the Ladies' Classic a year ago. The hold-up style has become as much part of the attraction of Zenyatta as the white socks on her hind legs and the understated dignity of her trainer, John Shirreffs, a horseman of the old school.

Happiest in the back barn nursing his horses rather than in front of a camera telling everybody how good they are, the 64-year-old Kansan has been forced into the limelight by his stable star's growing popularity. Zenyatta's last appearance, at Santa Anita, her hometrack, added an extra 14,000 to the crowd.

"She has this presence about her," says Shirreffs. "At Del Mar recently, the crowd were whistling and screaming at her and she was just looking around as if to say, 'What are you getting all excited about?'. She's got the sweetest temperament, you could lay down alongside her in the barn and use her as a pillow, but she knows when it's race day."

And she has an uncanny knack of knowing where the wire is, too. At Del Mar in high summer, her unbeaten streak seemed all but over a furlong out. "She just stretches and lowers that head of hers," laughs Shirreffs. "She always seems to get there." She did, by a head.

Shirreffs, in contrast, has given up trying to reach where he wanted to go. After returning from a spell of duty with the Marines in Vietnam, he was heading to Hawaii for the surf. Along the way, he stopped on a farm in California, found a job breaking yearlings for a man called Henry Freitas and never looked back. "Henry was one of those really good basic horse guys. He took a lot of care with each individual horse." Since taking out a trainer's licence in 1978, Shirreffs has shown the same qualities, quietly building a reputation on the west coast for his ability to bring the best out of often unfashionable horses such as Giacomo, who won the 2005 Kentucky Derby at odds of 50-1; Tiago, third in the Classic last year; and Bertrando.

"John can spend an hour just looking at a horse," says Jerry Moss, Zenyatta's owner. "He's a tough man to get out of the barn." Yet Shirreffs is the first to admit luck has played its part in the fairytale. When Zenyatta was paraded at the Keeneland sales four years ago, she was not looking her best. Others passed her by, allowing Jerry and Ann Moss to claim the big, spotty, backward-looking filly for a knockdown price of $60,000. "She was suffering from a skin disease and didn't look very attractive, which worked in our favour," Shirreffs says. "Now she's won 13 races in a row [and $2.7m in prize money]. That's amazing."

Though a highly respected breeder, Jerry Moss is better known as the "M" to Herb Alpert's "A" in A&M Records. He is still in the music business and still quarrying from the back catalogue of The Police, one of the label's most lucrative acts: Giacomo was named after one of Sting's sons and Zenyatta after the band's third album, Zenyatta Mondatta. The hit single Every Little Thing She Does Is Magic might even have been composed with Zenyatta in mind. Now only the colts, headed by the durable Irish horse, Rip Van Winkle, remain to be conquered. But with Summer Bird, Gio Ponti and Mine That Bird representing a formidable home challenge and a maximum field of 14, Zenyatta might be unable to take the liberties in running that she has done so far with her own kind. Neither should another fairytale ending be ruled out if, entering the twilight of a great career, Henry Cecil could win his first Breeders' Cup race with Twice Over, recent winner of the Champion Stakes.

Encouraged by an artificial surface at Santa Anita more suited to turf horses than the traditional American dirt, the Europeans are confident of surpassing last year's record of five victories. Thirty-six horses, the biggest contingent in 25 years, have made the trip to California to contest the 14 races worth $25.5m over two days. But if Zenyatta records a 14th straight victories, all of them will have to curtsy to the magical mare.