LOUISVILLE, Ky. – The baby-faced gene runs strong through the O’Brien family. Trainer Aidan has always looked much younger than his actual age, and his son, 18-year-old Joseph, could pass for 14 in a pinch. Aidan also has passed along another significant strand of DNA – high-class horsemanship. Joseph O’Brien rode in his first Breeders’ Cup race Saturday afternoon at Churchill Downs, and he won it in a romp, booting home St Nicholas Abbey to become, at age 18 years 161 days, the youngest rider to win a Breeders’ Cup race. “It’s a dream come true,” said O’Brien as he headed off to the post-race interview room. O’Brien has been at past Breeders’ Cups, but only as a morning exercise rider. He rode his first winner overseas in May 2009, won his first Group 1 in May 2011, and delivered St Nicholas Abbey to the winner’s circle in the $3 million Turf. The horse, of course, had a hand in the outcome. The 4-year-old St Nicholas Abbey ($15.60) might have run the race of his life, bursting from the back of the Turf pack to scorch past Sea Moon, who had taken the lead in midstretch. St Nicholas Abbey, racing in sixth and seventh as his stablemate, Await the Dawn, set splits of 24.92 seconds for the opening quarter-mile, 50.09 for the first half, and 1:14.67 for six furlongs, flew through his final quarter-mile, coming home in less than 23 seconds. Final time for 1 1/2  miles on a turf course upgraded from good to firm mid-card was 2:28.85. [bc_video_id:237931:]Brilliant Speed finished on length behind Sea Moon, followed by 2-1 favorite Sarafina, Stately Victor, Midday, Await the Dawn, Teaks North, and Dean’s Kitten. The winner, a son of Montjeu-Leaping Water (Sure Blade), was bred by Barton Bloodstock and Villiers Syndicate, and is owned by Derrick Smith, Susan Magnier, and Michael Tabor. St Nicholas Abbey was a top 2-year-old of 2009 but had a lost 2010 campaign, starting just once at age 3. This year went much better. St Nicholas Abbey finished third to modest competition in April, but moved far forward in his next two starts, winning a Group 3 before taking down Midday in the Group 1 Coronation Cup. Thirds in the King George behind Nathaniel and in the Prix Foy behind Sarafina were decent, and St Nicholas Abbey actually held the lead at the top of the stretch in the Prix de l’Arc de Triomphe before flattening out to fifth. “We knew since the Arc that he had really improved,” Aidan O’Brien said. The win gave O’Brien two on the day, six BC victories in his career, and was his third win in the Turf, following back-to-back scores by High Chaparral in 2002 and 2003. Joseph O’Brien is 5-foot-11, and probably does not have much time left as a flat jockey. However long his career lasts, he has a Breeders’ Cup victory for his father to treasure.