It was actually Grant that was setting effective ball screens earlier in the game. His ability to pick-and-pop allowed him to catch and hit an 18-footer. Then, his pop off the screen drew Christmas's defender on another possession, allowing Rakeem to get an offensive rebound put-back when Grant missed a 16-footer.
Grant's ability to roll to space is really helpful because defenses can't just play the dive to the hoop against him the way they can against Christmas and BMK (Let's face it--most teams just ignore BMK's roll). This prevents the hard-hedging/trapping that teams have used against Ennis; teams that want to trap risk Ennis taking one reverse dribble and passing to Grant for an open jumper.
Interestingly, when the team went to the stall game late to protect the lead, Fair started setting the ball screen, which created driving space for Ennis as the defense couldn't hedge as hard against this, either. This also permitted CJ to get the ball in an easier fashion than just curling off of screens. As a result, the team executed the stall game well today.
While we're talking about Fair, he also did a nice job of reading off-the-ball screens today. At least twice I saw him "bump" and fade to the corner on the pin-down screens, though I believe he missed the jumper both times (I haven't had a chance to re-watch the game yet, so I might be incorrect on that). Moving forward, he needs to curl his cut into the lane more often instead of popping to the perimeter almost every time. This would help him exploit the defense more effectively. It would also reduce the number of opportunities he has to turn the ball over because of his rather mediocre dribbling.