Glasgow 18 Ulster 27: Veteran marksman David Humphreys was yet again the destroyer in chief as the Warriors' Celtic League woes deepened at Firhill.
The former Ireland outhalf, who announced his retirement from the international stage last week, sent over five penalties to make sure his side stayed in the hunt for the championship.
Ulster - backed by a big contingent of noisy fans - made a storming start and broke the deadlock before even a minute was on the clock.
Scrum-half Isaac Boss sent a teasing chip into the home danger zone which Rory Lamont struggled to cope with.
Eventually he brought the ball under control, but was swamped by markers and Glasgow were penalised for entering the ruck illegally from side on.
Humphreys made no mistake with the kick, although the Warriors replied in positive fashion. Centre Andy Henderson made a break to release midfield partner Hefin O'Hare, but the pass had drifted marginally forward.
The home support were then furious with Welsh referee Tim Hayes when he ignored what looked like a clear case of off-the-ball obstruction after Colin Shaw had back-tracked to gather Humphreys' drop-out.
To add insult to injury, Ulster were awarded another penalty and justice was done as Humphreys watched his effort fly wide.
There was further controversy in the 19th minute which led to Boss bagging a try for the visitors. Shaw had every reason to appear aggrieved when he was penalised for an early tackle attempt.
Ulster surged across the 22-metre line before Boss squeezed over after confusing his markers with a clever dummy.
Humphreys converted but Glasgow responded by stepping up a gear to set up a penalty opportunity for Dan Parks following another powerful burst by Henderson.
Parks did the business to give his side a boost but Humphreys thumped over a long-range penalty after Warriors hooker Scott Lawson was warned for dissent.
And even worse was to come for the Scots when former Australian Test lock Justin Harrison snapped up Ulster's second touchdown.
Humphreys repeated the feat to leave Glasgow in disarray, but they rallied to create a fine try for substitute Johnny Beattie.
Parks traded penalties with Humphreys before dangerman Beattie set up another home score for O'Hare, Parks converting to ensure a tense finale.
Any prospect of the Warriors completing their comeback was dashed when Humphreys took his penalty tally to five. PA
