With the win, the Pacers improved to 8-0. The Grizzlies trailed in the second half by seven points and a big third quarter by Paul George put the game out of reach. George scored 13 of his 23 points in the third.
Roy Hibbert had five blocks for the Pacers, who kept the Grizzlies at 41 percent shooting from the floor.
The Pacers spread the wealth, with six players scoring in double digits -- highlighted by Stephenson's triple-double. Stephenson finished with 13 points, 11 rebounds and 12 assists.
Marc Gasol led the Grizzlies with 15 points, but Memphis struggled to find offense from any of its other players. Zach Randolph and Mike Conley were the only other Grizzlies to finish with double-digit points, scoring 12 and 11 points respectively.