Northampton fell short with a spirited second-half fightback as Leinster emerged 20-17 winners in their Investec Champions Cup clash at Croke Park to reach the final for the third straight year.
The repeat of the 2011 final was a mismatch for the first hour with wing James Lowe running in a hat-trick against the Gallagher Premiership leaders, who suffered from a high error count.
An 82,300-capacity crowd in Dublin watched the first England club to play at the home of Gaelic sport fire few shots until George Hendy crossed to give them hope of an upset.
Northampton then began to look more like the daredevil side that has taken the Premiership by storm this season and, when Tom Seabrook touched down with six minutes remaining, they had Leinster on the ropes.
But the four-time champions – who have lost to La Rochelle in the last two finals – clung on and will now face Toulouse or Harlequins, who meet on Sunday in the second semi-final, at Tottenham Hotspur Stadium on May 25.
Leinster start strongly before Saints launch valiant fightback
Perhaps in a sign of nerves, Saints started by giving the ball away cheaply and there was worse to come when a penalty close to their line saw Jamison Gibson-Park fling a long pass to Lowe, who cut inside to score.
The early onslaught continued when Lowe strolled over for his second try after Gibson-Park flicked on a superb offload from the charging Caelan Doris.
There was no respite for the underdogs as they gave up penalty after penalty, one of them at a pulverised scrum and another for offside at the restart, and Ross Byrne was able to kick another three points.
Northampton’s attack ignited briefly, creating a half-chance that vanished through poor timing, but a Fin Smith penalty at least got them off the mark.
Saints needed to score but instead, Lowe completed his hat-trick after a marauding run from Ryan Baird put Leinster on the front foot.
Two Saints attacks in the 22 were foiled by penalties but eventually, the pressure that was building on the home line told when Hendy’s chip and chase was spilt by Leinster and the wing seized the chance to touch down.
The second-half was proving far more of a contest and when Seabrook raced over with Smith converting, the result hung in the balance.
Leinster were paying the price for taking their foot off the visitors’ throat but they had the smarts and resilience to close out the tense final few minutes.
Lowe said afterwards to TNT Sports: “It’s such a special place Croke Park, the history that comes along with it is second to none and there’s not another stadium like it in the world. To be given the opportunity and privilege to play a club match here [is special].”
‘Something horrific almost happened – we were pretty fortunate’
More from Lowe, speaking to TNT Sports:
“We were able to build a score but we know Northampton are an amazing attacking side and we gave them too many opportunities. Something horrific almost happened!
“I don’t think we kicked well, me personally anyway, and we let their boys run riot. Credit to them, they pushed us until the end and we were pretty fortunate.
“We put in a performance we’re happy with but there are things we have got to tidy up if we want to go the whole way in this competition.
“We worked bloody hard to get ourselves into the driving seat and hopefully we’ll do better in the final than we have done in the last couple of years.”
Northampton boss Phil Dowson:
“I’m incredibly proud of the effort the lads put in, especially in defence. There’s frustration that we went close despite making so many mistakes.
“Fair play, Leinster are a good side and we pushed them close. We were way better in the second half and that was reflected on the scoreboard.”
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