After overcoming an early 15-4 deficit, the Razorbacks led most of the game, but the Leopards (2-6) got a three-pointer from Jason Kimbrough to take a 73-71 lead with 2:36 to play.
Cleveland hit a running 15-footer with 1:59 left to tie the game, and following a spinning layup by Alonzo Lane, Cleveland was fouled while making a layup and hit the free throw to give Arkansas a 78-73 advantage with 33 seconds remaining.
Joe Johnson added a free throw with 21 seconds to go and Teddy Gipson made a layup with 10 seconds left for the final margin.
After overcoming the sluggish start, Arkansas led by as much as nine in the first half and 10 early in the second half, but the Leopards, who earlier won at Virginia, stayed close enough to make a final run.
Kimbrough hit seven-of-12 three-pointers and led London with 21 points. Lelton Brown had 19 points and Rashod Johnson 11.
UA shot just 40 percent for the game (30-of-75), including 35 percent in the second half. The Razorbacks turned the ball over 19 times but forced 26 turnovers.
Gipson came off the bench to lead the Hogs with 15 points with nine coming in the second half. Blake Eddins added 10 points and seven rebounds. Jannero Pargo and Johnson scored eight each, and Lane had seven points and nine boards.
Arkansas, which beat EA Sports/California Southwest All-Stars, 112-87, in its first exhibition, opens the regular season at home on Nov. 17 against Tennessee State in the first round of the John Thompson Foundation Challenge Classic. UA and TSU play at 8:15 p.m., following the 6 p.m. opener between Southern Mississippi and Louisiana Tech.