Paris - Holders Leinster set up the first all-Irish Heineken Cup final on Sunday with a thrilling 19-15 victory over French side Clermont in Bordeaux.
Leinster scored the only try of the match - through Cian Healy - and had to show extraordinary defensive pluck at the end as Clermont, who were in the last four for the first time, battered away on their line.
However, the Irishmen held on and can emulate Leicester (2001/02) in being the only other side to defend their title when they play Ulster at Twickenham on May 19.
Leinster opened the scoring with an early penalty from Jonathan Sexton and Clermont suffered a blow in the 13th minute when Julien Malzieu, scorer of three tries in their quarter-final meeting two years ago, had to be replaced by Jean-Marcel Buttin.
Brock James levelled in the 18th minute with a penalty from in front of the posts as Clermont produced some incisive attacking rugby that had their opponents on the back foot.
However, every time they made inroads into the Leinster 22 they were penalised by referee Wayne Barnes, not always to the delight of the thousands of Clermont fans that had made the trip.
Barnes, though, further incurred their displeasure when he failed to penalise Leinster captain Leo Cullen in the 22nd minute after the lock punched Clermont prop Lionel Faure.
The latter's theatrical collapse to the ground may have swayed the referee in the Irishman's favour.
Clermont edged ahead in the 32nd minute as James landed a second penalty only for Sexton to make it 6-6 two minutes later with a penalty of his own.
James restored the French side's lead three minutes from the break with a penalty and added another for good measure on the stroke of half-time to send Clermont in 12-6 ahead.
However, Leinster came out a different side in the second-half and stormed into the lead through a brilliantly worked try.
South African hooker Richardt Strauss, a former Cheetah, released Rob Kearney, who tore through the Clermont defence and passed to Healy, who rumbled over the line to touch down.
Sexton converted for 13-12 and the Irish side extended their lead in the 48th minute with a stunning drop goal by Kearney from just inside the Clermont half for a 16-12 advantage.
James reduced the deficit with a penalty in the 53rd minute after missing one just prior to that but Sexton made it 19-15 with 17 minutes remaining.
In a dramatic finale, Clermont thought they had secured victory.
However star, French centre Wesley Fofana lost control of the ball as he attempted to ground it over the line and the French side's celebrations were brought to a juddering halt when the video referee told Barnes it was not a try.
Undeterred the French side laid siege to the Leinster line with a succession of penalties going their way but sterling Irish defence thwarted them.
The valiant attempts by the French finally came to nothing as Barnes whistled for a penalty in Leinster's favour and Sexton kicked it over the deadball line.
European Cup results:
Sunday: Bordeaux, France
Leinster (IRL) 19 Clermont (FRA) 15
Ulster (IRL) 22 Edinburgh (SCO) 19
Twickenham, May 19
Leinster (IRL) v Ulster (IRL)