Leinster brushed aside Ulster 43-20 at the Aviva Stadium to book a United Rugby Championship semi-final clash against the Vodacom Bulls in Pretoria next weekend.
Converted tries from Robbie Henshaw and James Lowe, as well as a Ross Byrne penalty, had Leinster leading 17-00 at half-time and well on course for a place in the last four.
Ulster, who had claimed two regular-season victories over their provincial rivals, had missed out on two close-range tries before finally getting on the scoreboard through John Cooney's 42nd-minute penalty.
David McCann, Stewart Moore and Michael Lowry also crossed for second-half tries for the battling visitors, but Leinster were rarely in danger and added four more tries to their first-half tally with Lowe, Jordan Larmour, Josh van der Flier and replacement Ross Molony touching down.
Leinster had no points to show for some early pressure, brought on by a maul steal from player-of-the-match Joe McCarthy.
A Cormac Izuchukwu break had the visitors threatening, but Matty Rea was unable to link with Cooney, and Nick Timoney was held up.
Izuchukwu's injury-enforced departure was a big blow for Ulster, as was the sight of Henshaw striding over for the game's opening try in the 21st minute after Jamie Osborne broke out of Moore's tackle to supply the assist.
Byrne converted and tagged on a 30th-minute penalty, and it was his inside pass that released Lowe to further increase Leinster's advantage
With Richie Murphy's Ulster side pressing to get back into the game before the interval, Greg Jones knocked on and Leinster, infringing again near their own line, avoided a yellow card before a key Ryan Baird lineout steal.
Cooney finally got Ulster up and running with a 43rd-minute penalty but Leinster quickly responded with Lowe deftly displaying his footballing skills along the left touchline, nudging the ball through before touching down and opening up a 19-point gap.
Cooney's precise skip pass put McCann over, as the game became looser. Crucially though, Leinster always had the answers.
Henshaw sent Larmour over out wide to make it 29-8, before Moore replied from a McIlroy kick to keep Ulster just about in the contest.
However, Van der Flier, set free by Osborne, slammed the door shut with 13 minutes remaining as another converted try saw Leinster move 36-15 ahead.
Molony scrambled over from five metres out give victorious Leinster a sixth try, although a valiant Ulster had the last word through Lowry, darting over from Nathan Doak's cross-field kick.
Scorers:
Leinster: Tries: Robbie Henshaw, James Lowe (2), Jordan Larmour, Josh van der Flier, Ross Molony. Conversions: Ross Byrne (5), Sam Prendergast. Penalty: Ross Byrne.
Ulster: Tries: David McCann, Stewart Moore, Mike Lowry. Conversion: John Cooney. Penalty: John Cooney.
Teams
Leinster: 15 Jimmy O’Brien, 14 Jordan Larmour, 13 Robbie Henshaw, 12 Jamie Osborne, 11 James Lowe, 10 Ross Byrne, 9 Jamison Gibson-Park, 8 Caelan Doris, 7 Josh van der Flier, 6 Ryan Baird, 5 James Ryan (c), 4 Joe McCarthy, 3 Tadhg Furlong, 2 Dan Sheehan, 1 Andrew Porter. Replacements: 16 Rónan Kelleher, 17 Cian Healy, 18 Michael Ala’alatoa, 19 Ross Molony, 20 Max Deegan, 21 Luke McGrath, 22 Sam Prendergast, 23 Ciarán Frawley.
Ulster: 15 Stewart Moore, 14 Mike Lowry, 13 Will Addison, 12 Stuart McCloskey, 11 Jacob Stockdale, 10 Billy Burns, 9 John Cooney, 8 Nick Timoney, 7 David McCann, 6 Matty Rea, 5 Cormac Izuchukwu, 4 Harry Sheridan, 3 Tom O’Toole, 2 Rob Herring (c), 1 Eric O’Sullivan. Replacements: 16 Tom Stewart, 17 Andy Warwick, 18 Scott Wilson, 19 Greg Jones, 20 Dave Ewers, 21 Nathan Doak, 22 Ethan McIlroy, 23 Jude Postlethwaite.
