Leinster set up an all-Irish Heineken Cup semi-final with Munster after grinding out a brutal 6-5 victory over Harlequins at the Stoop on Easter Sunday.
The result shows that two penalties from Felipe Contepomi trumped one try from Mike Brown, but this dog of a game wasn't decided by points on the board - it was about sweat, blood, toil and tears, with the shattered Irish side just managing to wring out one drip more than their shattered hosts.
Quins have had quite an adventure in Europe this season, but it ended in an ugly streetfight that taught them two painful lessons.
The first being that they still lack that intestinal fortitude that is borne from season after season of play-off rugby. The second that lightning rarely strikes the same place twice: Nick Evans missed a last-gasp drop-goal that would have put the Londoners through to Europe's last four.
Brian O'Driscoll's visitors, containing five of Ireland's Grand Slam heroes, were battered relentlessly but prevailed thanks to their ferocious never-say-die defence. These are the pretty boys of Irish rugby no more.
Points may have been at a premium - Leinster led 6-0 until the 66th minute - but it was a gripping contest played with brutal intensity.
The Irish province, semi-finalists on three previous occasions, moved through the gears in the third quarter but with 20 minutes to go Quins were back on the offensive.
England full-back Mike Brown dashed over but substitute fly-half Chris Malone, on for injured former All Black Nick Evans, missed the conversion.
Evans reappeared as a blood replacement as the game approached drop-goal age - was that a wink as Tom Williams left the field with a red substance around his mouth? The replacement angered Leinster's dug-out - especially as the Kiwi dropped back into the pocket late in the game.
Quins will be wondering how they failed to convert their vast amounts of possession into more points.
They staged a sustained assault on the Leinster line for long spells yet the breakthrough eluded them until Brown eventually crossed.
Quins were dominant at the start of the match, with Evans missing a kickable early penalty.
Ferocious defending from Leinster halted a succession of attacks on the gainline but their attempts to relieve the pressure were undermined by O'Driscoll and Isa Nacewa kicking out on the full.
Contepomi landed a penalty once they had escaped their half, but despite fielding an all-Ireland pairing of O'Driscoll and Gordon D'Arcy they were suffering in midfield.
The muscular Jordan Turner-Hall and his centre partner Gonzalo Tiesi created gaps while England winger David Strettle also caused problems with a positive run.
Leinster were being run ragged, with Contepomi flattened by the marauding Ugo Monye and Turner-Hall leaving a trail of bodies in his wake once again.
Only desperate defending kept them at bay and eventually their stranglehold was broken by an opportunist break from Rocky Elsom at the line-out that was halted by Monye.
O'Driscoll had been quiet by that stage but the Ireland captain burst into life with a minute of the first half remaining, chipping ahead and gathering the kick via a kind bounce.
The race for the line was on but Brown and Strettle just prevented him from touching down, although number eight Nick Easter was yellow-carded at the breakdown - a bad egg on his very own Sunday - and Contepomi was able to add his second penalty.
Worryingly for Leinster, O'Driscoll hurt his right shoulder during the move and when the second half resumed he was clearly still troubled by the injury.
The visitors appeared to have crossed through Rob Kearney in the 47th minute but Contepomi's pass to Nacewa was forward.
Evans, back after four weeks out with an ankle injury, lasted seconds longer before limping off.
Contepomi was sent to the sin bin for a swinging arm on Chris Robshaw but the Quins flanker, who collapsed to the floor, clearly made the most of what replays showed to be marginal contact.
Neither side could take a full-blooded encounter by the scruff of the neck, although Danny Care was only denied an inventive solo try when the jet-heeled Luke Fitzgerald intervened over the line.
Quins continued to pound away at Leinster's whitewash, the video referee saying they failed to ground the ball on one occasion.
For five minutes they camped on the visitors' line and Leinster were struggling to halt such a sustained onslaught, eventually cracking when Brown dived over.
Malone missed the conversion and then had to be carried off, leaving Brown to fall short with a long-range penalty in the 73rd minute.
Williams was the next to leave the pitch with a blood injury, enabling Evans to return.
The Kiwi lined-up a drop goal with a minute to go but it sailed wide, taking with it Quins' hopes of reaching the semi-finals.
Man of the match: Quins deserve more for their efforts - especially Danny Care, Jordan Turner-Hall and Ugo Monye. Brian O'Driscoll was his usual bustling, burrowing, brutal self, Leo Cullen bossed the line-out, Rob Kearney was a tower in a storm at the back, but it was industrious Rocky Elsom who really caught the eye. He has brought a steeliness to Leinster's formerly suspect pack.
Pens: Contepomi 2
Yellow card(s): Easter (Harlequins) - killing the ball (40), Contepomi (Leinster) - impeding the runner (50).
Harlequins: 15 Mike Brown, 14 David Strettle, 13 Gonzalo Tiesi, 12 Jordan Turner-Hall, 11 Ugo Monye, 10 Nick Evans, 9 Danny Care, 8 Nick Easter, 7 Will Skinner (c), 6 Chris Robshaw, 5 George Robson, 4 James Percival, 3 Mike Ross, 2 Gary Botha, 1 Ceri Jones.
Replacements: 16 Tani Fuga, 17 Mark Lambert, 18 Jim Evans, 19 Tom Guest, 20 Andy Gomarsall, 21 Chris Malone, 22 Tom Williams.
Leinster: 15 Rob Kearney, 14 Isa Nacewa, 13 Brian O'Driscoll, 12 Gordon D'Arcy, 11 Luke Fitzgerald, 10 Felipe Contepomi, 9 Chris Whitaker, 8 Jamie Heaslip, 7 Shane Jennings, 6 Rocky Elsom, 5 Malcolm O'Kelly, 4 Leo Cullen, 3 Stan Wright, 2 Bernard Jackman, 1 Cian Healy.
Replacements: 16 John Fogarty, 17 Ronan McCormack, 18 Trevor Hogan, 19 Sean O'Brien, 20 Simon Keogh, 21 Girvan Dempsey, 22 Shane Horgan.
Referee: Nigel Owens (Wales)
Touch judges: Nigel Whitehouse (Wales), Hugh Watkins (Wales)
Assessor: Patrick Robin (France)
Television match official: Roy Marfleet (England), Derek Bevan (Wales)