Despite facing a heavy first half wind Leinster turned round at 10-10 and were able to use the wind to their advantage in the second period.
The visitors collected two tries in the first half through Ben Gissing in the opening minutes and Christian Warner just before the interval and although Andy Maxwell was able to keep the home side in the game with their only try of the half it was Leinster who looked the more assured outfit, after Wallace had missed three relatively easy penalty chances.
Leinster were camped in Ulster territory in the early part of the second half, and David McAllister put them ahead with two penalties before Bryn Cunningham reduced the gap to a point when he rounded a superb Ulster backline move.
Despite a renewed Ulster vigour Brian O’Meara extended the visitors lead through a huge penalty kick and in the closing stages Brian O’Riordan secured the win with a touchdown following a Victor Costello break. O’Meara’s conversion left Ulster feeling the rare sensation of home defeat.