The second-ranked Wildcats advanced to play the winner of Saturday's semifinal between Appalachian State and No. 1 Montana next weekend in Chattanooga, Tenn.
The game was slowed by five instant replay reviews, but the only one that was overturned made perhaps the biggest difference.
Trailing 13-7 late in the third quarter, Villanova embarked on a time-consuming drive that appeared to end when a third-and-7 pass play fell incomplete. The play was overturned by replay, giving Villanova first-and-goal at the 6, and quarterback Chris Whitney scored from a yard out on fourth down with 10:57 left to take the lead.
Villanova didn't score until there was about 9 minutes left in the third quarter, when wide receiver Matt Szczur scored on a 62-yard run out of the Wildcat formation. The touchdown made it 10 consecutive games that the junior has scored, and was his eighth touchdown run of the year.
Sixth-ranked William & Mary rode the arm of quarterback R.J. Archer, who completed 21 of 35 passes for 239 yards - although most of it came on one play early in the game.
Archer found junior receiver Cameron Dohse up the sideline, beating Villanova cornerback Eric Loper for a 98-yard touchdown. The play gave the Tribe a 7-0 lead with 10:45 remaining in the first half, and was Archer's first touchdown pass of the playoffs.
Brian Pate added a field goal as time ran out for a 10-0 halftime lead.