At Thomas College in Waterville, Greg Duff threw six strong innings and Curtis Worcester recorded his second save with a perfect seventh inning as Bangor improved to 8-0.
Brian Rouleau had a bases-loaded triple for the winners.
Sam Dexter had a double and two singles for Messalonskee of Oakland and Reid Nutter pitched a complete-game in defeat.
Messalonskee 101 000 0 2-4-1
Bangor 200 000 4 6-5-0
Duff, Worcester (7) and Frost; Nutter and Gettig