The victory is the first for the Benedictine men's basketball program since winning the 1967 national championship over Oklahoma Baptist.
"The toughest one is the first game in the tournament, and I think this one may be especially tough because its the first time we've ever been here in a long time," Benedictine head coach Ryan Moody said after the game. "I thought the guys battled really hard and found a way against a really good team down the stretch."
The game had the look of a Benedictine home game with more than half of the fans wearing black and red, but Westminster took control in the first half.
The Griffins shot 48-percent from the field in the first 20 minutes, and forced the Ravens to commit 14 turnovers.
BC trailed by as much as 12, but scored the first nine points of the second half to swing momentum back to their side. Wallrapp had 17 of his game-high 19 points after halftime.
Jallen Messersmith was the only other Benedictine player in double figures with 15 points.
The Ravens focus now turns to Vanguard on Friday. They beat Life University 103-94 Wednesday evening.