Ulster scored 15 points in a four-minute spell midway through the second half to ended a run of seven straight defeats at the hands of Cardiff Blues.
The home side led 15-8 at half-time but disintegrated in a second period in which they rarely crossed the halfway line.
Ulster, dominant up front throughout, began to string a few passes together to claim their first Magners League win on the road since September.
In the early stages the Blues had displayed a refreshing willingness to throw the ball around, a fine miss pass by Ceri Sweeney sending full-back Chris Czekaj away and left-wing Tom James collecting a loose kick to race 60 yards before being brought down just short of the line.
A home try duly arrived when mercurial Kiwi centre Casey Laulala picked up a charged-down Ulster clearance before skipping past two defenders to the line. Sweeney converted.
Ulster hit back, making ground down the left before spreading it right for wing Craig Gilroy to cross with a spare man outside him.
A long-range penalty from Ian Humphreys put Ulster ahead and the Blues also lost influential number eight Xavier Rush - who changed his mind about a summer move to Ravenhill - through injury.
A deliberate knock-on to prevent Czekaj delivering a try-scoring pass to Tom James brought a yellow card for Ulster full-back Adam D'Arcy, and while he was absent James claimed his deserved touchdown after hooker Rhys Thomas and flanker Michael Paterson had been held up on the line.
Sweeney slotted a penalty after visiting flanker Chris Henry was also guilty of a deliberate knock-on and Ulster suffered a further blow when South African Muller was knocked out and had to retire to the stand.
But everything changed in the second half as the visitors brought on the cavalry in the shape of international centres Andrew Trimble and Paddy Wallace and, with D'Arcy restored to the action, they began to look more dangerous.
Humphreys narrowed the gap with a penalty and then dinked a kick ahead which the lively Gilroy retrieved before slicing past two defenders to the posts.
D'Arcy powered down the left to cross for another score straight after the resumption and the game had a totally different look.
Substitute Willie Faloon galloped 30 yards to clinch a bonus point with the Blues' defence in disarray, and when Gareth Williams inexplicably tried a grubber kick that failed to breach the Ulster line, Wallace had a free run to score.
Humphreys' third conversion hammered in the final nail.