Karl Noon's 73rd-minute solo strike handed the spoils to Bangor, but it was referee Simon Jones who took centre stage at Farrar Road.
The visitors claimed the goal was offside, but it was the man in black who had allowed them back into the game with another contentious decision.
Bangor were leading two-nil when Michael Johnston was punished for a perfectly executed tackle on Ged Courtney and when keeper Paul Smith failed to hold Sam McNutt's free kick, Chris Herbert netted from the rebound.
Nomads then levelled four minutes later when Peter Hoy was caught out of position and McNutt teed up Danny Forde for a simple tap in.
McNutt missed a gilt-edged chance to put Nomads in front and a minute later Noon got the winner.
The Citizens had dominated early exchanges with former City keeper Paul Pritchard produced a superb save to deny Sion Edwards.
Ashley Stott missed his chance before Chris Seargeant found Edwards who turned Tom Baker to score from 10 yards.
Edwards hit the post with a corner kick and Stott went close seconds after the restart but was not to be denied on 52 minutes, following-up for a rebound after Pritchard had parried Marc Limbert's strike.
Stott should have restored the two goal cushion on 80 minutes, but failed to get a touch just two yards out after Noon had caught Chris Williams in possession.
The match almost ended in more controversy when the official allowed play to continue after Lee Webber was flattened by a high kick and Smith saved at the feet of subs Stuart Cook and John McAllister.
Stats and report courtesy of welsh-premier.com