Paul Egwuonwu added 14 points and seven rebounds for the Bobcats (4-7, 1-2 Big Sky).
Montana State led 52-38 with 7:35 remaining when Portland State went on a 15-1 run to tie the game at 53-53 with 3:05 to go.
Two jumpers by Egwuonwu and four free throws from Moon put the Bobcats ahead 61-53 with 12 seconds left. But McMullen hit a 3-pointer with 5 seconds remaining, then made a steal and another 3-pointer with 3 seconds left to make it 61-59.
Michael Dison hit 1 of 2 free throws for Montana State before a desperation 3-pointer by Dre Winston at the buzzer came up short.
Guard Naz Mitrou-Long, whose 2015-16 season ended in December due to hip problems, has been granted a hardship waiver for the coming season, Iowa State said.
As the Sooners look to life without superstar Buddy Hield and his sidekicks, it's clear their unseasoned players will need to grow up fast.
The Central Intercollegiate Athletic Association says it won't move its headquarters, its basketball tournament or other conference championships from North Carolina, despite