The Grizzlies (20-6, 16-1) held onto first place in the Big Sky Conference despite playing without star point guard Will Cherry and forward Mathias Ward.
The Bobcats (11-16, 8-10) trailed 59-43 midway through the second half but went on a 16-3 run behind 11 points from Flavien Davis, who finished the game with 30.
Montana extended the lead back to 70-60 with 2:58 to go. Montana State came back with an 8-1 run, but couldn’t get a shot off on its last possession as Antonio Biglow was called for charging with 3.3 seconds to play.
Spencer Coleman and Kareem Jamar both had 14 points for the Grizzlies, who made 11 of 22 3-pointers compared to just 3 of 14 for the Bobcats.Christian Moon had 14 points for Montana State.