As far as the Breeders' Cup World Thoroughbred Championships is concerned, repeat customers are more than welcome. But while many Breeders' Cup winners have tried to repeat their glory, only a select few have succeeded.Of course countless horses that didn't win have also given it another shot, or shots.In the 21-year history of the Breeders' Cup, only six horses have come back to win again. And, this isn't like winning the same race at the same track two years in a row. Not that that is easy either, but since the Breeders' Cup has a new home each year, this requires crossing the finish line first over two surfaces.(Of course the two juvenile races cannot be won in repeat fashion, but those winners can come back to compete in other races.)This year, four horses are trying to win back-to-back Breeders' Cup races: Ashado returns in the Emirates Airline Distaff (gr. I); Singletary in the NetJets Mile (gr. IT); Ouija Board in the Emirates Airline Filly & Mare Turf (gr. IT); and Better Talk Now in the John Deere Turf (gr. IT).Never have two horses repeated in the same year, so should two of the four aforementioned winners do so, it would be breaking new Breeders' Cup ground.The first horse to repeat was Miesque, who won the Mile with relative ease in both 1987 and 1988. The daughter of Nureyev, trained in France for owner Stavros Niarchos by Francois Boutin, won by 3 1/2 lengths at Hollywood Park, the chart noting she was "under a hand ride." It should be noted the course was firm because a year later at Churchill Downs on a dreary wet afternoon, she showed she could also handle a good course.Again under Freddie Head, Miesque toyed with her competition -- if you can call it that -- winning by four lengths over Steinlen, who was a longshot that day but would come back to win the race the next year.Four of the six repeat winners have done so in grass races, one of the exceptions being Bayakoa, who won the Distaff in 1989 and 1990 for trainer Ron McAnally.Owned by Frank and Janis Whitham, Bayakoa was simply too much to handle once she pounced on the lead. At Gulfstream Park in 1989, she took the lead before the field had run six furlongs and cruised home under Laffit Pincay Jr. by 1 1/2 lengths. At Belmont the following year, she made it look even easier, though who knows what would have happened had Go for Wand not broken down. Bayakoa won by 6 3/4 lengths.Lure was certainly one of the best American turf milers in many years, and he proved it in the Breeders' Cup. Bred in partnership by Claiborne Farm and Gamely, he raced in the Claiborne silks to win the Mile at Gulfstream in 1992 and at Santa Anita in 1993. Trained by Shug McGaughey and ridden both years by Mike Smith, the son of Danzig won wire-to-wire by three lengths and then came back to win nearly wire-to-wire by 2 1/4 lengths.Three of the six repeat winners have been milers, and perhaps the most awesome feat of any of the six was dual Mile winner Da Hoss. Trainer Michael Dickinson had the son of Gone West ready to win the Mile in 1996 at Woodbine, and then after a lengthy layoff, brought him back to win the race two years later at Churchill. Owned by Prestonwood Farm and Wall Street Stable, Da Hoss won under Gary Stevens by 1 1/2 lengths, and then John Velazquez rode him in 1998 to just prevail by a head.The richest race on the card, the $4 million Classic (gr. I), has once been won twice by the same horse, Tiznow , who did so by the scantest of margins. Trainer Jay Robbins sent out Tiznow with jockey Chris McCarron at Churchill in 2000 and Belmont in 2001. The son of Cee's Tizzy, owned by Michael Cooper and Cecilia Straub-Rubens the first year and Cees Stable the second, won by a neck and a nose.The final repeat winner gets a special footnote because High Chaparral won the Turf outright in 2002 at Arlington Park, and then was involved in the only dead-heat for win when he finished on even terms with Johar at Santa Anita the next year. Owned by Michael Tabor and Sue Magnier, High Chaparral was trained by Aidan O'Brien. Mick Kinane rode him both times.