Darrun Hilliard helped out with 15 points for the Wildcats (12-1, 1-0 Big East), who shook off their first loss of the season -- a 78-62 defeat at the hands of No. 2 Syracuse Saturday.
Butler's Kellen Dunham had forced overtime on a score-tying jumper with 21.5 seconds left in regulation, and also hit back-to-back baskets in the extra time to keep the Bulldogs close.
But he couldn't connect on a 3-point try in the closing seconds and Villanova hung on for a triumph in the conference opener.
Dunham finished with 22 points and Elijah Brown added 19 off the bench for Butler (10-3, 0-1).