Leinster were pushed all the way by a spirited Bath side but did enough to secure an 18-15 win in the Champions Cup quarter-final.
A visit to Marseille or Brighton now awaits Matt O'Connor's side as they won the physical battle and remained composed to see off a real threat from Bath.
Leinster might not seem quite like the force of old this season but their supreme record in European knockout rugby shone through yet again.
The Irish giants had won four out of their last five quarter-finals prior to facing Bath and ten of their last 12 knockout games.
Bath aspire to sit at a similar level when it comes to the greats of Europe and you sense their time is coming, despite Saturday's defeat in the Dublin sunshine. Too many handling errors and penalties however let them down.
The exuberance of their backs didn't fade on the big stage with George Ford underlining his Test class by scoring and creating key tries either sides of half-time for Bath as they refused to let Leinster run away with the contest. Ford struggled here against Ireland back in March but there were no jitters a month on.
Two weapons for Leinster though ultimately drove them to victory, the boot of Ian Madigan and the power of their pack as they churned out penalties in the scrum and held their nerve in the closing stages. Jamie Heaslip, so often their talisman, was outstanding.
A frantic opening was settled down when Madigan slotted his first penalty after the scrum did good work in the Bath 22, with Ford unable to reply with his first effort with a 45-metre attempt.
The England number ten however undid the Leinster defence with a fine run after Francois Louw's initial break. Ford skipped and dummied his way through the defence to go over untouched and give Bath the game's first try and also the lead.
Bath's discipline would have to be outstanding to win on the road in Dublin but they paid the price when Carl Fearns went off his feet, Madigan making it 6-5, before Bath went a man down following Anthony Watson's yellow card after he took out Rob Kearney in the air from the restart.
Madigan added two penalties while Bath were a man down to stretch the lead before landing a fifth effort just before the interval, his fine touch giving Leinster a ten-point advantage and leaving Bath with plenty of work to do at half-time.
A nasty but accidental collision between Kyle Eastmond and Fergus McFadden saw the Irishman depart with a concussion. His replacement, Zane Kirchner, was denied a try in the corner thanks to a fine try-saving tackle from Micky Young.
Leroy Houston's time with Bath has been a real success and the Australian made an impact with barnstorming carry to fracture the Leinster defence in a warning for what was to come.
Ford identified a huge gap in Leinster's rearguard and burst through, his captain Stuart Hooper there in support to crash over as Bath cut the gap on the scoreboard to just three at 15-12.
That powerful Leinster scrum through remained dominant, with Martin Moore making an immediate impact as Madigan made it six from six with 50 minutes gone.
With threats like Eastmond, Watson and Ford, Bath always teased the possibility of more long-range attacks but the pressure was beginning to tell.
Peter Stringer received a rousing reception from the Dublin crowd on his return to the old site of Lansdowne Road to give Bath the experience they needed.
Leinster however held the advantage of the clock and the lead but six points never felt like a safe enough advantage with Ford controlling the territory.
Ford added a penalty after Sean O'Brien was overeager at the ruck to set up an excruciating finish with Leinster ahead by just three points.
Louw's breakdown expertise came good with a crucial penalty win to set Bath up in the Leinster half. The ultimate test of composure for the visitors and discipline for the hosts, Ford threw a forward pass at the worst time for his side's hopes.
Bath came within a whisker when Alafoti Faosiliva's chargedown caused panic in the Leinster ranks, Jimmy Gopperth their saviour as he scurried back in time, as the Leinster fans went through agony.
This though was Leinster's day, Bath infringing at the ruck in the dying stages as Ireland's finest advance to the last four.
Pens: Madigan 6
Tries: Ford, Hooper
Leinster: 15 Rob Kearney, 14 Fergus McFadden, 13 Ben Te'o, 12 Ian Madigan, 11 Luke Fitzgerald, 10 Jimmy Gopperth, 9 Isaac Boss, 8 Jamie Heaslip (c), 7 Sean O'Brien, 6 Jordi Murphy, 5 Mike McCarthy, 4 Devin Toner, 3 Mike Ross, 2 Sean Cronin, 1 Cian Healy.
Replacements: 16 Richardt Strauss, 17 Jack McGrath, 18 Marty Moore, 19 Tom Denton, 20 Dominic Ryan, 21 Eoin Reddan, 22 Gordon D'Arcy, 23 Zane Kirchner.
Bath: 15 Anthony Watson, 14 Horacio Agulla, 13 Jonathan Joseph, 12 Kyle Eastmond, 11 Matt Banahan, 10 George Ford, 9 Micky Young, 8 Leroy Houston, 7 Francois Louw, 6 Carl Fearns, 5 Dave Attwood, 4 Stuart Hooper (c), 3 Kane Palma-Newport, 2 Rob Webber, 1 Paul James.
Replacements: 16 Ross Batty, 17 Nick Auterac, 18 Max Lahiff, 19 Matt Garvey, 20 Alafoti Faosiliva, 21 Peter Stringer, 22 Sam Burgess, 23 Tom Homer.
Referee: Jerome Garces (France)
Assistant referees: Christophe Berdos (France), Patrick Pechambert (France)
TMO: Eric Gauzins (France)