London Irish's assault on the Heineken Cup finally ran out of steam on Saturday with an 11-11 draw with Leinster at Twickenham.
The result leaves Northampton visiting Munster once again in a repeat of Friday night's clash, while Leinster will probably end up hosting Stade Franšais or Clermont at the RDS if results on Sunday go as expected.
It was Jonny Sexton who rescued the Leinstermen with a 40m drop goal with two minutes to go, after Chris Malone's penalty looked to have both secured a quarter-final spot for the Exiles and handed Leinster a likely away trip in the quarters.
The Exiles bounced back from 8-3 down at half-time with a vibrant final quarter, but after Malone had given them the lead with a penalty - he missed three other shots at goal, including a conversion of his own try - the Exiles turned the ball over at the restart and Sexton struck as sweet a kick as you like through the posts.
In an extraordinary finale, Malone had two drops at goal in the final minute to seal the win that would have seen Irish heading to Munster instead of Northampton, but it was not to be for the fly-half, who looked as though he had swallowed a wasp at the final whistle.
The champions didn't need to do much to qualify, a losing bonus point would have been enough. The Exiles needed four tries to even stand a chance and the burden of expectation clearly weighed upon them as they delivered a tetchy performance. Delon Armitage epitomised the jangling nerves by dropping the ball three times in the opening five minutes alone (he didn't get much better). Chris Malone's glaring early penalty miss was also symptomatic; another miss early in the second half rather set the seal on the defeat.
While the Exiles ran the ball hither and thither with a little too much abandon to be effective, Leinster waited patiently, defended dilligently, turned over ball regularly and then took the chances to land the sucker punches clinically.
In a match where open space and constructive rugby was at a premium Gordon D'Arcy provided the spark with a sumptuous out and in running line to make the break. While it did not lead directly to a try, it cranked up the pressure on the Exiles, whose defensive shell cracked surprisingly easily three minutes later as Isa Nacewa was left in oodles of space on the left for the try.
Leinster broke the deadlock through Sexton's fifth-minute penalty from 40 metres and their defence held firm as their opponents battled away in response.
There was a nervousness in Irish's play. Malone shanked wide what should have been a straightforward penalty in the 14th minute and both the Australian fly-half and centre Seilala Mapusua attempted drop-goals that ended up way off target.
Ireland fly-half Sexton was unlucky to see a penalty on the half-hour mark crash against the upright and the ball was snapped up by Exiles winger Topsy Ojo, who embarked on a weaving 40-yard run that ended when he made a forward pass.
Malone found his range five minutes later for 3-3 but Leinster made the ideal riposte before half-time through Nacewa's 38th-minute try.
Moments earlier, the New Zealand-born winger's pass to the lively Gordon D'Arcy, that sent the centre over for a try, was harshly adjudged forward by referee Nigel Owens. But from the resulting scrum, Irish were barged off the ball and ceded possession to Leinster number eight Jamie Heaslip, before Eoin Reddan sent over Nacewa in the left corner.
A 46th-minute dust-up involving Exiles hooker David Paice and Leinster prop Cian Healy saw the latter take 10 minutes in the cooler, but Irish did not take advantage.
Malone missed another routine three-pointer while Mapusua butchered a potential try-scoring chance when he knocked at the end of a decent move that started with a crossfield kick by Malone to Ojo.
Play began to get stretched as Irish got more desperate and with Healy back on, Leinster regained the whip hand. Their midfield pairing of D'Arcy and Brian O'Driscoll carried an ever-present danger, one break from the former nearly setting Shane Horgan away.
Malone's try, then, came somewhat against the run of play. After Mapusua had got over the gainline with a powerful run through the middle, Malone received the ball in the next phase and ignored men outside him to barge over for a 67th-minute score that needed the say-so of the video referee.
Crucially, though, Malone missed the easy conversion, leaving the score tied at 8-8.
It set up a tense finale and Malone turned down the chance of a drop-goal in the 74th minute as an initial opportunity came to nought.
He made amends with two minutes to go with a penalty that looked to have won it for Irish, but Sexton's last-gasp drop saw them knocked out.
For London Irish:
Pens: Malone 2
Drop goal: Sexton
London Irish:15 Delon Armitage, 14 Topsy Ojo, 13 Elvis Seveali'i, 12 Seilala Mapusua, 11 Sailosi Tagicakibau, 10 Chris Malone, 9 Paul Hodgson, 8 Chris Hala'Ufia, 7 Steffon Armitage, 6 Richard Thorpe, 5 Bob Casey, 4 Nick Kennedy, 3 Faan Rautenbach, 2 David Paice, 1 Clarke Dermody.
Replacements:16 James Buckland, 17 Dan Murphy, 18 Paulica Ion, 19 Gary Johnson, 20 Kieran Roche, 21 Peter Hewat, 22 Peter Richards, 23 Ryan Lamb,
Leinster:15 Rob Kearney, 14 Shane Horgan, 13 Brian O'Driscoll, 12 Gordon D'Arcy, 11 Isa Nacewa, 10 Jonathan Sexton, 9 Eoin Reddan, 8 Jamie Heaslip , 7 Shane Jennings, 6 Kevin McLaughlin, 5 Nathan Hines, 4 Leo Cullen(c), 3 CJ van der Linde, 2 Bernard Jackman, 1 Cian Healy.
Replacements: 16 John Fogarty, 17 Mike Ross, 18 Stan Wright, 19 Malcolm O'Kelly, 20 Sean O'Brien, 21 Paul O'Donohoe, 22 Shaun Berne, 23 Girvan Dempsey.
Referee: Nigel Owens (WRU).