Leinster went in at the break with a commanding advantage before Ulster finally got on the scoreboard courtesy of a John Cooney penalty.
Lowe showed off his soccer skills to chalk up his second try, kicking down the line from Byrne’s cross-field kick and going over although Byrne hit the upright with the conversion attempt.
Ulster were trailing 22-3 but they kept charging forward and were rewarded with McCann trotting over the line from a superb Cooney reverse pass.
Cooney missed the conversion and Leinster were soon scoring again with Larmour going in for a converted try.
Moore gathered from Ethan McIlroy’s smart chip to sprint over for Ulster’s second try with Cooney this time adding the two points.
Leinster were in no mood to ease off and van der Flier strode in to score try number five before Ross Molony put the icing on the cake by driving over with four minutes left.
Both tries were converted and there was still time for Ulster to grab the last score of the game as Lowry outpaced Ciaran Frawley before touching down, although John Cooney missed with the conversion.
Leinster: Jimmy O’Brien; Jordan Larmour, Robbie Henshaw, Jamie Osborne, James Lowe; Ross Byrne, Jamison Gibson-Park; Andrew Porter, Dan Sheehan, Tadhg Furlong; Joe McCarthy, James Ryan (capt); Ryan Baird, Josh van der Flier, Caelan Doris.
Replacements: Ronan Kelleher, Cian Healy, Michael Ala’alatoa, Ross Molony, Max Deegan, Luke McGrath, Sam Prendergast, Ciaran Frawley.
Ulster: Stewart Moore; Mike Lowry, Will Addison, Stuart McCloskey, Jacob Stockdale; Billy Burns, John Cooney; Eric O’Sullivan, Rob Herring (capt), Tom O’Toole; Harry Sheridan, Cormac Izuchukwu; Matty Rea, David McCann, Nick Timoney.
Replacements: Tom Stewart, Andy Warwick, Scott Wilson, Greg Jones, Dave Ewers, Nathan Doak, Ethan McIlroy, Jude Postlethwaite.
Referee: Andrew Brace (IRFU)
