London Irish (3) 11
Tries: Malone Pen Malone (2)
Leinster (8) 11
Tries: Nacewa Drop goal: Sexton Pen: Sexton
Nacewa's first-half try helped end London Irish's last-eight hopes
Jonathan Sexton struck a late drop-goal as European champions Leinster drew with London Irish to knock the English club out of the Heineken Cup.
Chris Malone had minutes earlier sent over a dramatic penalty to give Irish an 11-8 lead and the Exiles also missed two late drop-goal attempts.
Isa Nacewa's try gave Leinster an 8-3 lead after penalties from Sexton and Malone, whose own try levelled it.
The result means that Northampton now qualify in place of London Irish.
It was a dramatic ending to what had been an otherwise error-strewn game.
Sexton sent over an early penalty for Leinster after Irish had been penalised for a scrum infringement but Malone wasted an opportunity to level, missing from virtually in front of the posts.
Sexton was having an equally erratic day, hitting the post with a penalty on the half hour, before Irish eventually levelled through Malone, with the European champions penalised for not retreating.
Gordon D'Arcy created and finished a fine move for Leinster but his try was disallowed for an earlier forward pass.
From the resulting scrum, which Leinster won against the head, the visitors drove to the London Irish line and eventually passed out to Nacewa on the wing to dive over unchallenged.
The conversion was missed but after Leinster's Cian Healy was sent to the bin for punching, Malone was again wide with a penalty.
But he made up for that miss with a try on 65 minutes, stepping inside the Leinster defence to bundle over and level the score.
Malone, however, missed with the conversion and although he later sent over a penalty, Sexton responded almost immediately with a long-range drop goal to level the game at 11-11.
Irish later missed two drop-goals in a heart-stopping finale as Leinster held out to draw the game and advance to the quarter-finals.
London Irish head coach Toby Booth:
"Strange as it may seem, my first emotion is I'm proud of what we've achieved in this Heineken Cup campaign, to be honest.
"To be undefeated against the team that holds the trophy, and to go to their back garden and win, tells me we can live at the top table of European rugby.
"The damage was not done tonight, it was done in rounds two and five. While you can have some indifferent performances in the Guinness Premiership, if you have them in the Heineken Cup, you can't recover.
"It's part of the continued improvement that we need, this ability to perform when we feel less threatened. It's about moving from happy underdog to expectant favourite and we need to learn that at this club."
Leinster head coach Michael Cheika: "After losing that first game to London Irish, maybe we had to reset our goals.
"But we hung in there, and the way it's worked out we have managed to get a home draw. It's a positive finish to the pool campaign."
Cheika praised his team for their defensive display against their English opponents.
"It's something we pride ourselves on.
"We know it's a way to exact pressure and maybe we can get tries out of that defence.
"It's an important backbone to our game. They were a pretty attacking team and we had to be aware of the threats they bring. We didn't get broken too many times and in games like this, it's great to have confidence in your defence."
London Irish: D Armitage; Ojo, Seveali'i, Mapusua, Tagicakibau; Malone, Hodgson; Dermody, Paice, Rautenbach, Kennedy, Casey, Thorpe, S. Armitage, Hala'ufia.
Replacements: Richards for Hodgson (33), Murphy for Dermody (71), Ion for Rautenbach (60), Johnson for Casey (80), Roche for S Armitage (60).
Not Used: Buckland, Hewat, Lamb.
Leinster: R Kearney; Horgan, O'Driscoll, D'Arcy, Nacewa; J Sexton, Reddan; Healy, Jackman, Van der Linde, Cullen, Hines, McLaughlin, Jennings, Heaslip.
Replacements: Fogarty for Jackman (30), Ross for Van der Linde (54), O'Kelly for Cullen (61), Wright for McLaughlin (51), O'Brien for Jennings (57).
Not Used: O'Donohoe, Berne, Dempsey.
Sin Bin: Healy (47).
Ref: Nigel Owens (WRFU).