Lillard, the nation’s leading scorer, hit 8-of-14 from the 3-point line for the Wildcats (12-3, 4-0 Big Sky). Teammate Scott Bamforth added 21 points.
Chehales Tapscott led Portland State (7-9, 1-3) with 26 points and Nate Lozeau had 13 points.
Weber State battled back from a 15-point first half deficit and tied the score at 71 after Lillard hit his eighth 3-pointer of the night with 8:27 left to play. The Wildcats went up 78-75 on a runner by Jordan Richardson with 4:35 remaining, then closed out the Vikings by holding them to just one field goal in the final four minutes.
Weber State shot 53 percent from the field and Portland State shot 50 percent.