Mystik Dan won the 150th Kentucky Derby on Saturday, snatching victory over Sierra Leone at the wire in a scintillating first leg of US flat racing’s Triple Crown at Churchill Downs. Trained by Kenny McPeek and ridden by Brian Hernandez Jr., Mystik Dan squeezed through on the inside going into the final straight and held off — by less than a nose — the late charges by second-favorite Sierra Leone and Japanese raider Forever Young with a photo needed to sort out the order. After the fury of the race, McPeek and Hernandez had to wait several minutes to see their horse, who went off at 18-1, confirmed as the winner. “That was the longest two minutes I’ve ever felt in my life, waiting for them to hang that number up,” Hernandez said. “It was exciting when we hit the wire, but I wasn’t sure if we won.” Fierceness, the pre-race favorite trained by Todd Pletcher and ridden by John Velazquez, challenged around the final turn but faded late to finish 15th in the field of 20. The exciting finish capped a celebratory week at Churchill Downs, where last year’s Kentucky Derby was overshadowed by a string of horse deaths that reached 12 before racing was shut down last June.