Leinster ended Ulster's 21-match unbeaten run at Ravenhill by claiming a deserved 26-15 victory in Saturday's Celtic League clash.
Ulster (10) 15:
Tries: Maxwell, Cunningham.
Leinster (10) 26:
Tries: Gissing, Warner, O'Riordan.
Pens: McAllister 2, O'Meara.
The key to Leinster's win was going in level at 10-10 at the interval despite having played against the wind.
Ben Gissing and Christian Warner scored Leinster's first half tries with Andy Maxwell touching down for Ulster.
Bryn Cunningham's try kept Ulster in touch in the second half but Brian O'Riordan's try made the game safe.
Despite playing against a stiff breeze, Leinster made a great start with Ben Gissing notching a try in the sixth minute after Leo Cullen had soared to win a line-out just short of the Ulster line.
The home side hit back three minutes later with Paddy Wallace slotting a penalty.
By the 12th minute, Ulster were ahead with Andy Maxwell's winning the chase for the corner after Neil Doak had stroked a deft kick over the Leinster defence.
Maxwell looked in a suspiciously offside position but referee Nigel Williams awarded the score and Wallace's conversion increased Ulster's lead to five points.
However, Wallace's kicking let him down during the remainder of the first half.
He failed with three penalties in a 15-minute period as Ulster failed to turn decent possession into points.
Andy Maxwell attempts another burst for Ulster
The third failure came moments after Leinster number eight Des Dillon had been sin-binned for handling in a ruck.
Right on half-time, Ulster frustration increased when the overlapping Christian Warner crossed right in the corner to level matters at 10-10 after a delightful move.
With the wind advantage to follow, Leinster must have been delighted with their first half's work.
The third quarter was spent mainly in Ulster territory and 50th and 53rd minute penalties from fly-half David McAllister edged the visitors six points ahead.
Leinster missed a glorious chance to add to their lead in the 59th minute when James Norton stepped into touch when a pass inside to one of several colleagues would have yielded a certain try after an interception in their own '22.
Three minutes later, Ulster were right back in the game when Bryn Cunningham finished off a glorious backline move in the corner after superb work by Jonny Bell and Maxwell.
Wallace missed the difficult conversion but the try gave the Ulster side renewed belief and some good backline moves kept the ball in the Leinster half.
However, Leinster maintained their composure and when Tommy Bowe was penalised for holding on in the tackle as he burst over half-way, Brian O'Meara punished the mistake by thumping over a huge penalty.
The crucial closing minutes of the game were played deep in the Ulster half and replacement scrum-half Brian O'Riordan made the game safe with another touchdown after a Victor Costello break.
O'Meara added the conversion and Leinster's celebrations after the final whistle moments later, indicated how important they viewed their first win over Ulster in four years.
Ulster: Cunningham; Bowe; Steinmetz, Bell, Maxwell; Wallace, Doak, S Best, Shields, Moore, Mustchin, Frost, N Best, Ward (capt), Wilson.
Replacements: McCormack, Brady, McCullough, Feather, Campbell, Mallon, Young.
Leinster: Norton; McWeeney; Warner, Quinlan, Brown; McAllister, O'Meara; Byrne, Hickie, Coyle, Cullen (capt), Gissing, McCullen, Jennings, Dillon.
Replacements: Nebbett or O'Donnell, Blaney, Potts, Costello, O'Riordan, Lewis, Kilroy.
Referee: Nigel Williams (WRU).