The win was the second straight for the Razorbacks, who survived the hot-shooting Tigers and guard Frankie Sullivan's five second-half 3-pointers.
Young added 22 points and Mardracus Wade had 12 for Arkansas (11-5, 2-1 Southeastern), which now has won seven of its last eight games. Powell had 21 points in the second half and overtimes, finishing with his second-highest point total of the season.
Sullivan led Auburn (8-8, 2-1) with 26 points, 23 of them after halftime. He was 5 of 11 on 3-pointers, and the Tigers were 11 of 25 overall from behind the arc.
Mississippi State freshman guard Malik Newman will withdraw from the NBA draft, but sources told ESPN he might explore other opportunities besides returning to Mississippi State.
Seton Hall sophomore Isaiah Whitehead will stay in the NBA draft and not return for his junior season.
Washington State's trio of Josh Hawkinson, Conor Clifford and Ike Iroegbu have withdrawn from the NBA draft and will play their senior season with the Cougars.