For months she has been untouchable. Her chestnut coat, still sleek and effeminate, is now punctuated with muscle, and the observable maturity has shaped her into a running machine. Race after race, each victory as overpowering as the last, have left her competition in shambles. She's drilled them on the lead. She's stalked and pounced just the same. Nobody can seem to keep up. So with the 20th Breeders' Cup World Thoroughbred Championships set to erupt on Oct. 25 at Santa Anita Park, the clear choice to win the $2-million Breeders' Cup Distaff (gr. I) is...not Azeri? A month ago, the idea would have sounded absurd. But Azeri's defeat in September's Lady's Secret Breeders' Cup Handicap (gr. II) leaves Sightseek as the horse to beat in the nine-furlong Distaff, which is the first Breeders' Cup race on the card. Not that she hasn't earned the role on her own merits. After opening the year on a Southern California slide, the daughter of Distant View retreated to the East Coast base of trainer Bobby Frankel. There, the metamorphosis took place. The 4-year-old filly became a beast, reeling off four dominating wins--all grade Is--by a combined 25 1/2 lengths. Her run has indeed been formidable. Despite the tour de force, though, Sightseek is unlikely to run the same circles around her Distaff rivals. There remains, of course, the glaring statistic that the Juddmonte Farms homebred, so imposing on eastern tracks, is still 0-for-3 at Santa Anita. Is she simply a fan of New York and Kentucky's deeper surfaces, or is the Sightseek of fall a different animal entirely than the Sightseek of last winter? The one apt to answer those questions--and the principal obstacle in Sightseek's Distaff quest--is the reigning queen herself, Azeri. Casting aside her Lady's Secret letdown, the result, it was later revealed, of a dormant infection, the defending Horse of the Year has been routinely brilliant in 2003, extending her graded stakes winning streak to 11. Her untimely illness, however, has now shed doubt on a presumed defense of her Distaff title. The strength of Azeri's pre-Breeders' Cup works, according to trainer Laura de Seroux, will decide her fate. Wild Spirit, a stablemate of Sightseek, was ultra-impressive all year after arriving from South America, but Frankel has decided to give her some time off and rest her for next year's campaign. Others, obviously, are willing to take on the top pair. Take Charge Lady has won nearly $2.5 million, but will her hex continue? The Dehere filly has two forgettable Breeders' Cup flops already--the 2001 Juvenile Fillies (gr. I) and last year's Distaff--she finished sixth each time. Are Adoration, Elloluv, and Lady Tak really good enough? True, they are all worthy opponents. In the minds of many, the race boils down to two standouts, and it is the matchup between Sightseek and Azeri that already has 'em drooling over the possibilities. Then again, there is one other filly who stands to give the Distaff a little extra kick. Since December, she's won four major stakes--all graded--at Santa Anita, which just happens to be her home turf. She, too, is a durable, developing sort entering the Breeders' Cup on a visible upswing. But for all of Got Koko's achievements, there is one that gives the daughter of Signal Tap a unique edge. She is the only horse on the planet to have defeated both Sightseek and Azeri. Brace yourselves. This one could get ugly.