LOUISVILLE, Ky. – Carl Nafzger has won the Kentucky Derby twice and was voted into the Racing Hall of Fame, but he might be best known, both in racing and outside it, for one of the greatest unscripted moments in sports history, his impromptu narration to owner Frances Genter of Unbridled’s charge to victory in the Kentucky Derby. It happened 25 years ago. Nafzger was 48 at the time. Genter was 92. Unbridled’s exercise rider, who had arrived the previous year on a work visa, was a 24-year-old Australian named Ian Wilkes. Their lives were changed forever by the featured race at Churchill Downs on May 5, 1990. Unbridled was a 10-1 shot in that Derby, his support having waned since a third-place finish in the Blue Grass Stakes following a victory in the Florida Derby. It turned out to be a classic Nafzger move. He became known as one of the best trainers ever at pointing for a main target, having his horse at his absolute best when it counted most. Nafzger did it later that year with Unbridled in the Breeders’ Cup Classic and in 2007 with Street Sense in the Kentucky Derby. But even though the Derby win with Unbridled helped catapult Nafzger’s career, his joy in the moment was focused solely on what Genter had just achieved after decades in the sport. His narration, and the interplay between he and Genter captured by ABC, illuminated Nafzger’s personality. “We’re up to third,” Nafzger said to Genter as Unbridled and jockey Craig Perret advanced on the turn. “He’s taken the lead. He’s taken the lead. C’mon, Unbridled. He’s taken the lead. He’s taken the lead. He’s on the lead, Mrs. Genter, he’s on the lead. He’s gonna win! He’s gonna win! He’s gonna win! He’s gonna win!” By now, Nafzger was shouting over the crowd’s din. Genter put her left hand over her mouth, seemingly stunned by what was unfolding. “He’s the winner. He’s the winner, Mrs. Genter,” Nafzger said as the horses began to pass their box. “There he goes, right there. He’s the winner. He’s the winner. He’s the winner, Mrs. Genter.” Nafzger gave Genter a gentle kiss, then a hug. His voice now a mixture of exhaustion and jubilation, Nafzger said: “He’s the winner. He’s the winner. He won it. He won it. You won the Kentucky Derby. Oh, Mrs. Genter, I love you.” At no point did Nafzger say “we” had won or use the word “I” in reference to him having trained a Derby winner in his first attempt. It was telling, and authentic. “Mrs. Genter made the whole deal,” Nafzger recalled one morning this week at Churchill Downs, where this year’s Derby will be run Saturday. “She was like everyone’s mother, or grandmother. It truly was Mrs. Genter’s Derby.” Nafzger ended up being wired for sound in the most serendipitous way. After the Florida Derby win, ABC found old videos of Nafzger during his bull riding days on “Wide World of Sports” telecasts and presented it to him. It was also discovered that the daughter of a man for whom Nafzger had once worked, the former Karen Morris, was now married to Curt Gowdy Jr., who was the producer of the Derby telecast for ABC. So, at the Derby, Nafzger agreed to a request to wear a microphone. The original plan was simply to talk to him for some last-second thoughts before the race, which Jim McKay did just as the horses were loading into the gate. When the race ended, the production truck had seen what the isolated camera had captured. “Just the facial expressions were amazing,” recalled Stephen Nagler, who was the associate producer on that show. During the post-race coverage, when the replay first began to air, hosts Al Michaels and Dave Johnson talked over the initial part of the narration, not realizing what was being said. A high-level ABC executive screamed into their earpieces, “Lay out, lay out,” which means to be quiet and let the sound play. And thus the whole world got to hear Nafzger’s call to Genter. “It was such a touching thing,” Nagler said. “It captivated people beyond the sports world.” Nafzger, though, was unaware that it had aired. “That night, people were saying how nice it was,” Nafzger said. “I’m thinking, ‘What are they talking about?’ ” It wasn’t until a few nights later that Nafzger saw a replay of the whole telecast at a friend’s house. His initial reaction: “I felt almost embarrassed that I let my emotions get to me.” Wilkes had helped lead Unbridled onto the track and hand him off to the pony. He watched the race from some bleachers near where the tunnel meets the racetrack, standing alongside his wife, Tracey. “I remember when they came by the first time, you could see the dirt hitting him, and he was just swelling up,” Wilkes said. “He was traveling so well. I was yelling and screaming so much in the stretch I knocked Tracey off the bench.” That fall, right after the Breeders’ Cup, the Wilkeses returned to their native Australia, their work visas having expired. Nafzger told Wilkes a job awaited him if he wanted to return. “Three years later, I called him up and said, ‘Does that offer still stand?’ ” Wilkes said. Wilkes worked for Nafzger as an assistant until 2006, when Nafzger decided to semi-retire. Magnanimous as always, he turned most of his operation over to Wilkes. “Who else would turn over all those horses?” Wilkes said. Wilkes has gone on to win a Breeders’ Cup Classic himself, with Fort Larned. He has 70 horses. Nafzger has two horses in his name but is at the barn every day, joking that he’s now Wilkes’s assistant. “I like horses, and I like Ian,” Nafzger said. The relationship between Nafzger, his wife, Wanda, and the Wilkeses is more than co-workers. The Nafzgers never had children but are very close with Ian, Tracey, and their two now-adult children, Shelby, 24, and Brodie, 22. “They’re like parents to us, and grandparents to our kids,” Wilkes said. “I’ve always said they’re like our American parents.” Unbridled, voted the champion 3-year-old male of 1990, raced through the end of his 4-year-old year, retiring with a record of eight wins from 24 starts and more than $4.4 million in earnings. He got off to a promising start at stud, siring the likes of 1996 Derby winner Grindstone and Triple Crown race winners Empire Maker and Red Bullet, but died from colic on Oct. 18, 2001, at the age of 14. “He was a gentle giant. The day he died ...” Nafzger’s voice caught, his eyes welled up. “When you ran him,” Nafzger said after composing himself, “he gave you everything he had. If he got beat, it was my fault. He taught me a lot. He was a great teacher. He was quite a horse.”