Villanova overcame an 18-point deficit, and Reynolds and Fisher were at the center of it all.
The Wildcats trailed 36-18 with five minutes left in the first half. But they got hot from 3-point range. Fisher was 2-for-3 from behind the arc and 9-for-10 from the free-throw line.
Reynolds' biggest shot was an off-balance 3-pointer with Cliff Hammonds in his face just before the shot clock expired. Hammonds fouled him on the play, then dropped his head in disbelief after the ball banked off the backboard and went in.
Reynolds missed the free throw, but his bucket gave Villanova its first lead of the game, 50-49 with 11:56 remaining.
Clemson nearly folded from there, looking every bit like a team that hadn't been in the NCAA Tournament in 10 years.
But Villanova helped the Tigers get back in it.
The Tigers trailed 64-57 with 3:44 remaining, but Terrence Oglesby made five consecutive free throws -- three after he was fouled on a 3-pointer.
Clemson's Demontez Stitt tied it at 66 with two more free throws with 1:55 to go, but the Wildcats retook the lead by making nine of 10 from the stripe over the final 1:37.
Stitt led the Tigers with 14 points.