The No. 1-ranked Vikings improved to 23-0 with the win, and Knox finished at 12-12. Lawrence's victory sets up a showdown with Carroll College in Saturday's championship game at 3:00 p.m. The winner receives an automatic berth in the NCAA Division III Tournament.
Ryan Kroeger led a balanced Lawrence attack with 18 points. Keven Bradley added 15 points, and Chris Braier had 14 points and a game-high eight rebounds. Andy Hurley chipped in with 10 points, and Kyle MacGillis had a game-high eight assists.
Jason Maclin led Knox with 16 points, and Nick Reineck and Jeff Zick had 13 points apiece.
Knox kept it close in the first half with the help of some 3-point bombs, but Lawrence attacked Knox's 2-3 zone and hit 8 of 14 3-point attempts before the break.
The Vikings went on a 16-3 run over the final 5:49 of the first half to pull away. Doug Kadison scored all six of his points in that stretch with a pair of 3-pointers.
The Vikings led 46-29 at the break, but Knox battled back to trim the lead to nine points on Cole Monaghan's layup with 14:23 remaining.
Lawrence then steadily pulled away and led 71-55 when Maclin scored on a layup with 6:48 left. The Vikings scored the game's next seven points to seal the victory.