Flemings' basket with 3:43 remaining in overtime made it 56-55 and gave the Rainbow Warriors (1-2) the lead for good. The Bengals (1-1) pulled to 60-59 on Amorrow Morgan's two free throws with 1:09 left, but Kareem Nitoto and Amis each made two free throws for Hawaii to make it 64-59 with 7.5 seconds left.
After both teams traded free throws, Morgan hit a 3-pointer to cut the lead to 66-64 with 1 second left. But Adhar Mayen made a free throw for Hawaii and Amis intercepted Idaho State's inbound pass as time expired.
Morgan led Idaho State with 26 points and Demetrius Monroe added 14.
The game was part of ESPN's College Hoops Tip-off Marathon and started at 11 p.m. local time.
Reggie Witherspoon, who spent more than 13 seasons coaching at Buffalo, is returning to the city to coach Canisius College.
North Carolina Hall of Fame men's basketball coach Roy Williams is recovering from knee-replacement surgery.
Sparkling facilities are one thing, but Tim Miles needs to regain the momentum of Nebraska's 2014 run to the NCAAs if it is to play with the big boys.