Ulster was first to move through the gears, twice opting for the corner instead of a shot at the posts in what was a taste of things to come.
The second surge paid dividends when thrower, James McCormick, got around in support of the pack to ground the ball in the fourth minute.
The Leinster scrum then put the home side in the right position to strike. A dangerous attack was oiled by Chris Cosgrave’s pass and Craig Adams’ finish in the left corner, which Matthew Lynch nailed for 7-5 in the 12th minute.
A slip in concentration allowed Leinster to counter up the left. It meant centre, Ross Taylor, had to nail James Culhane in the tackle, and Jake Flannery angled the ball inside the Leinster 22.
But Hugh Cooney’s long left-footed ball created enough uncertainty for Leinster to roll forward, Cormac Daly picking up the try from close range, Lynch’s extras taking it to 14-5 in the 22nd minute.
Swift work by James Girvan on the floor allowed Flannery’s penalty to look to the lineout again until Tadgh McElroy pinched the ball at the tail.
Leinster’s scrum dominance put pressure on, with Rory Telfer’s intervention preventing further damage – with Ulster remaining vigilant in defence as the half-time whistle sounded.
Rob Lyttle picked it up again in the next half when he quickly closed down Cosgrave after Ben Murphy put him into space. However, Leinster’s scrum continued to engineer penalties.
Daniel Leane took Sean O’Brien’s pass off the ground for Leinster’s next try, converted by Charlie Tector for 21-5 in the 57th minute.
There was something of a stalemate for a stretch, neither side capable of stringing together a clinical attack as defences ruled.
Then, Henry McErlean took the eye in cutting loose up the right and slipping the ball to Cosgrave for Leinster’s fourth try, Tector adding the conversion in the 71st minute.
Ulster continued to battle all the way to finish when a powerful maul provided the platform for Zac Solomon to touch down and for Conor McKee to convert.
Scorers
Ulster
Tries: James McCormick, Zac Solomon
Cons: Conor McKee
Leinster
Tries: Daniel Leane, Cormac Daly, Craig Adams, Chris Cosgrave
Cons: Matthew Lynch, Charlie Tector