Wagner held Lafayette to 21.7 percent shooting in the first half and entered halftime with a 34-20 lead, but the Leopards outscored the Seahawks 38-29 in the second half to keep things interesting.
Lafayette shot 54.2 percent in the second half and scored 11 points from the free throw line to help mount a comeback, but Wagner's lead was too great.
Jared Mintz scored 23 points and grabbed seven rebounds for the Leopards in the loss.
Lafayette scored 21 of its points from the free throw line as the Leopards shot 84 percent as a team.
Wagner maintained its lead thanks in large part to 11-for-22 shooting from behind the 3-point line.