Willliams, the second-year forward out of the University of Memphis, scored 17 of his points in the second half. Ike Diogu also scored 17 points for the Pacers, and Jamaal Tinsley added 16 points and 10 assists. Mike Dunleavy and Kareem Rush had 15 apiece.
Casey Jacobsen and Damon Stoudamire led the Grizzlies with 16 points each, while Andre Brown finished with 13 points and nine rebounds.
Indiana, which enjoyed a 28-point lead before defeating Memphis 122-115 on Oct. 17, built a 35-point advantage in the first half Friday.
This time, Memphis didn't rally enough to even make it interesting. The Pacers shot 69 percent from the field in the first half to take an 81-48 lead into the half.
The Pacers reached the 100-point mark with more than 4 minutes left in the third period, extended the advantage to 40 and carried a 110-74 lead into the fourth.
Each team finished the preseason without key big men. Jermaine O'Neal and Troy Murphy missed the game for Indiana, while Pau Gasol, Memphis' leading scorer and rebounder last season, was out nursing a left ankle sprain.
Memphis also got a scare early when Mike Miller went down after a dunk in the opening minutes. The Grizzlies' leading 3-point shooter immediately went to the locker room, but returned a short time later.
Indiana showed its running pace early and shot well, hitting 15 of its first 19 shots for an early 15-point lead. The Pacers' offense was helped by a lackluster defensive effort by the Grizzlies in the first half that led to a 26-5 Indiana advantage in fast-break points before halftime.
The Pacers had 36 fast-break points in the game to 9 for Memphis.
Granger scored all 15 of his first-half points in the opening quarter to lead the Pacers, while Diogu had 14 and Tinsley added 12.
Stoudamire had 11 for Memphis at the break.