Striker Andrew Waterworth made it four goals in five games as Glentoran won at Premiership newboys Ballinamallard.
Waterworth punished slack defending in shooting in on 16 minutes but home defender Mark Stafford headed United level eight minutes later.
Jay Magee thumped in Glentoran's second goal after the home defence failed to clear Stephen Carson's free-kick.
Martin Murray made it 3-1 to the Glens and a Leon Caters own goal eight minutes from time completed the win.
The results takes Eddie Patterson's Glens up to fourth with nine points from their five league fixtures and they are away to Dungannon Swifts on Saturday.