Lawrence (5-1) faces either Westmont or Susquehanna University at 9:00 p.m. Central time Thursday for the tournament title.
Kyle MacGillis scored a season-high 17 points to pace Lawrence. Freshman Andy Hurley turned in his finest game of the season with 14 points. Fourteen players scored for Lawrence.
Tommy Magnuson scored eight points to pace Lewis and Clark (2-4).
The Vikings broke the game wide open early. Lawrence led 10-8 and went on an 18-0 run to grab a 28-8 advantage with 9:24 left in the first half. Hurley and MacGillis had seven points apiece during that outburst.
The Vikings led 39-11 at the half and limited Lewis and Clark to only 3-for-27 shooting from the field in the opening 20 minutes. The Vikings also forced 12 Lewis and Clark turnovers in the first half.
Lawrence led by as many as 48 points in the second half.