The RedHawks were 4 of 8 from the field in overtime, while the Flyers (1-1) missed all three of their 3-pointers after regulation.
Miami overcame 40.7 percent shooting for the game (24 of 59) by grabbing 11 of its 33 rebounds on the offensive glass. Mavunga led the RedHawks on the boards with 11 rebounds. Bill Edwards also had a double-double for Miami with 14 points and 10 rebounds.
Freshman Brian Sullivan scored 14 points, including four 3-pointers, and Josh Sewell added 10 points for Miami, which defeated Dayton for the first time in six meetings.
Paul Williams scored 20 points and Kevin Dillard added 11 for Dayton, which had the final possession of regulation, but missed a shot from half court.