The Blues arrived in Belfast on the back of successive wins over Edinburgh and Treviso – results that had seen them top the Rabo Direct Pro 12 standings with a maximum 10 points.
Life under the stewardship of Justin Burnell and Gareth Baber had started superbly but it was last season’s beaten Magners League semi-finalists and Heineken Cup quarter-finalists who were convincing winners in Round 3 at Ravenhill.
Darren Cave’s quick-fire try double left the Blues with a mountain to climb as the home side established a 17-0 lead at the interval.
Cave finished off Craig Gilroy’s brilliant break with 10 minutes remaining of the first half before using the wet conditions to slide in from distance in following quick hands from midfield partner Nevin Spence moments later.
Xavier Rush saw yellow for a high tackle on 53 minutes as the Blues’ huge task got even tougher in front of a partisan home crowd.
Ceri Sweeney struck the Blues’ only points with a quarter of an hour left to play but conditions ensured their chances of conjuring up the three tries they needed were always going to be slim.
The result sees Ulster leapfrog the Blues at the head of the table, with Brian McLaughlin’s men now having won all three fixtures this term.
The Blues sit second prior to Saturday’s action when the Ospreys, Munster or the Scarlets could push them down the table.
