A Declan Danaher try and 15 points from the boot of Peter Hewat secured London Irish a place in the semi-final of the Heineken Cup back in 2008.
The victory saw the Exiles into their first ever Heineken Cup semi-final with a huge win against French Top 14 side Perpignan.
The visitors went ahead through a Percy Montgomery penalty goal, but two Peter Hewat penalties put Irish into a 6-3 lead.
The South African World Cup winner Montgomery levelled it at 6-6 but soon after Danaher crossed for a try to put Irish five points ahead.
Montgomery cut the gap with his third penalty but Hewat added three more of his own after the break to seal the win.
Scorers: London Irish: Tries Danaher; Penalties: Hewat (5); Perpignan: Penalties: Montgomery (3)
15 Hewat, 14 Ojo, 13 Tiesi, 12 Mapusua, 11 Tagicakibau, 10 Catt, 9 Hodgson, 1 Dermody, 2 Paice, 3 Rautembach, 4 Kennedy, 5 Casey, 6 Danaher, 7 S. Armitage, 8 P. Murphy
Replacements: Lea'aetoa, Coetzee, Hudson, Thorpe, D. Armitage, Richards, Geraghty
15 Montgomery, 14 Manas, 13 Marty, 12 Grandclaude, 11 Plante, 10 N. Laharrague, 9 Cusiter, 1 Chobet, 2 Tincu, 3 Mas, 4 Alvarez, 5 Hines, 6 Vaki, 7 Tonita, 8Tuilagi.
Replacements: Guirado, Freshwater, Bozzi, Porcu, Durand, Hume, Chouly