The Bears (5-4, 3-4 Big Sky Conference) took over on their 11 with 44 seconds to play after a Viking punt. Jacob Knipp, who threw for 270 yards, hit Alex Wesley for 58 yards on the first play and then Knipp hooked up with Riek for 28 yards to the 2. After one run was stopped, Riek punched in the game winner.
The Vikings (7-2, 4-2) scored twice in the fourth quarter, taking their only lead on Steven Long's 25-yard burst up the middle with 5:17 to play. Earlier, Alex Kuresa - who threw for 250 yards - hit Darnell Adams for a 64-yard TD.
Northern Colorado, which had 13 penalties for 161 yards, turned the ball over on downs at the PSU with 2:16 to play.