The Buffalo Bulls, the tournament's No. 8 seed, earned a 76-61 upset over the No. 5 Ball State Cardinals on the back of Will Regan's spectacular performance. He scored 36 points for the Bulls on Wednesday, shooting 11 of 17 and 5 of 7 from three-point range. He was also 9-of-9 from the free-throw line for the Bulls.
Ball State led by as many as 10 points near the end of the first half, but Buffalo answered with an eight-minute run to take a 55-44 lead with about 15 minutes to play in the game.
Buffalo will play the No. 4 Kent State Golden Flashes in Thursday's quarterfinals.
The No. 7 Eastern Michigan Eagles pulled away early in the second half for a 58-47 win over the No. 11 Miami RedHawks in Wednesday's second game. Four players scored in double figures for Eastern Michigan, led by Derek Thompson's 14.
The Eagles will play No. 3 Western Michigan on Thursday.