|Leinster (13) 30|
|Tries: Ringrose, Leavy, Lowe Cons: Sexton 2, McFadden Pens: Sexton 3|
|Saracens (12) 19|
|Tries: Cowan Cons: Farrell Pens: Farrell 3, Bosch|
Leinster knocked out Champions Cup holders Saracens in Dublin to set up a home semi-final against Scarlets.
Garry Ringrose crossed early on, before Johnny Sexton and Owen Farrell traded penalties as back-to-back winners Saracens trailed 13-12 at the break.
Leinster looked to have run away with it through tries from Dan Leavy and James Lowe before Blair Cowan replied.
But the top seeds held on to end Saracens' hopes of a third straight trophy.
Leinster, who remain unbeaten in this year's competition, will hosts last season's Pro12 champions Scarlets at the Aviva Stadium in Dublin in the first semi-final.
Racing 92, who beat 2017 runners-up Clermont earlier on Sunday, face Munster in Bordeaux in the other last-four tie.
Leone Nakarawa, Marc Andreu and Boris Palu all crossed for Racing as they shocked hosts Clermont at the Stade Marcel-Michelin 28-17.
Leinster rely on first-half defence
Leinster, boosted by the return of a number of Ireland's Grand Slam-winners, echoed their country's triumph in the Six Nations with a clinical and physical performance in Dublin, interspersed with moments of individual brilliance.
The hosts set Aviva Stadium alight after just four minutes with an electric move from deep, finished by returning centre Ringrose.
Lowe eased past Wales international Liam Williams on the wing before offloading to Isa Nacewa, who sent Ringrose in under the sticks.
But after a flash of Irish magic, it was Saracens who dominated the first half with 64% possession and 67% territory - and the reigning champions' targeting of Sexton forced the playmaker to momentarily lose his composure.
George Kruis, Maro Itoje and Richard Wigglesworth all put in big hits on the halfback, the final one from Wigglesworth a debatable shoulder charge.
Having just extended Leinster's lead, Sexton kicked the ball away as he trotted back to the restart - a move which was duly punished by the long boot of Marcelo Bosch.
After the match, Sexton offered up a wise reflection that "small moments win big games", and nodded to his side's defensive efforts in the final moments of the first period, to repel two Saracens line-outs on their own try-line.
Leavy completes commanding performance
Saracens, having crept into the knockout stages through the final qualifying place, were outclassed in the second half by the unbeaten Leinster.
Having conceded a try after just four minutes, the visitors were once again caught napping at the start of the second period as two of Ireland's Grand Slam stars combined.
Leavy, acting as scrum-half at the breakdown, played a quick one-two with James Ryan and dived through a hole in the Saracens defence.
The Ireland flanker, having impressed in the Six Nations, was the standout player in Dublin - he made 14 tackles in defence while adding 82 metres, three clean breaks and beating four defenders in attack.
Leinster all-but extinguished Saracens' Champions Cup run on the hour mark when a huge team effort saw Lowe driven over from close-range.
Cowan did reply from a good Saracens line-out drive but if failed to ignite a comeback and it was Leinster who ended the game in the ascendency as they marched into the semi-finals.
|Champions Cup semi-finals - 21/22 April|
|SF1: Leinster v Scarlets - Aviva Stadium, Dublin|
|SF2: Racing 92 v Munster - Stade Chaban-Delmas, Bordeaux|
Leinster: Kearney; McFadden, Ringrose, Nacewa (c), Lowe; Sexton, McGrath; Healy, Cronin, Furlong, Toner, Ryan, Fardy, Leavy, Murphy.
Replacements: Tracy, McGrath, Porter, Ruddock, Deegan, McCarthy, Carbery, O'Loughlin.
Saracens: Goode; L Williams, Bosch, Barritt (c), Maitland; Farrell, Wigglesworth; M Vunipola, George, Figallo, Itoje, Kruis, Isiekwe, Burger, Wray.
Replacements: Brits, Barrington, Lamositele, Day, Cowan, Spencer, Lozowski, Wyles.