Ulster wing Craig Gilroy, 19, capped his senior debut with a brace of tries as Ulster fought back with 29 unanswered second-half points to defeat the Blues in Cardiff.
The home side went into the break 15-8 ahead but had no answer to Ulster’s dominance in the second-period as the province ended their seven-match losing streak against their Welsh opponents in style.
Gilroy, who scored a try in each half at the Cardiff City Stadium was over the moon with his debut.
"We're delighted with the win. I wanted to go out and prove myself and make sure I didn’t screw up on my debut,” he said.
“To get two tries is a big bonus.
“For the first one Robbie Diack offloaded out of the tackle to me and I managed to squeeze in the corner, the second Humph put in a brilliant kick and I got a lucky bounce. I saw the cover was coming across pretty fast so I decided to step inside past their fullback and covering 10 and it came off.
“I've been playing a couple of games for the Ravens and have also been involved with the Irish Under 20's so I'm just happy to have been given an opportunity.
”When you have wingers like Simon Danielli and Andrew Trimble it’s difficult to get involved and I’m just over-the-moon to have played well.
“After losing the last few games it’s a big win. We have worked hard in the last two weeks and it really came together for us.
“We haven’t beat Cardiff in a while so to come here and win with a bonus-point is another big plus."