The Pilots (6-1), off to their best start since going 6-0 in 1995-96 when they last made the NCAA Tournament, were up 27 when the Vikings (4-2) went on a late 18-2 run to trail by 11 with 3:22 left, forcing Portland starters back into the game.
Thomas van der Mars added 19 points and 14 rebounds for Portland, which had a 44-27 rebounding advantage with its 16 offensive rebounds matching PSU's defensive total.
DeShaun Wiggins and Tieqbe Bamba had 13 each for PSU, which trailed 41-24 at the half. Bryce White and Tim Douglas had 12 apiece.
The Vikings made 17 of 33 shots in the second half to finish at 40 percent but the Pilots shot 31-62 for the game, 16 of 28 in the second half.