The Vikings trailed by 10 points at the half but made a late run. Lawrence was down 46-40 with less than four minutes left when Jason Holinbeck made a pair of free throws and Kyle MacGillis followed with a jumper to cut the lead to 46-44 with 2:57 left.
Kyle Bechler followed with a 3-pointer for Westmont (8-2), but Chris Braier answered with a pair of free throws. That was all the Vikings would get as Lawrence missed two shots and turned the ball over twice in the next two minutes.
Dan Evans paced Lawrence with 11 points and Brendan Falls had 10. Braier was held to eight points and 11 rebounds. Lawrence shot only 36 percent from the floor (18-50), including 14.3 percent (3-21) on 3-pointers.
Nick Debban had 17 points and Bechler added 15 for Westmont, which is a NAIA Division I school.