Marcus Britt scored the game-winning basket with 16.3 seconds remaining in overtime, and Arkansas ended a 10-game losing streak against Kentucky with a 77-76 victory at Bud Walton Arena.
Terrence Jones gave Kentucky the lead, 76-75, on a jumper with roughly 80 seconds to go in OT, and the Wildcats got the ball back when Marshawn Powell missed at the other end.
Brandon Knight, however, threw a bad pass in the lane that was picked off by Jeff Peterson, who raced down the court and hit Britt in stride with a bounce pass for the go-ahead layup.
Knight then missed twice from the left side, the last a contested baseline 10- footer that was knocked out of bounds by Arkansas with 1.8 seconds to go. Knight had another chance to redeem himself, but his off-balanced three fell well off the mark, denying his coach, John Calipari, his 500th career win.
Rotnei Clarke scored 26 points while Powell added 22 points and 10 rebounds for the Razorbacks (17-10, 6-7 SEC), who have won three of four overall.
Knight, who also missed two potential winners at the end of regulation, finished with 26 points, eight rebounds and five assists in the loss, the fourth straight for Kentucky (19-8, 7-6) on the road.