London Irish kept alive their slim hopes of qualification from Pool 2 after they demolished Racing-Metro 34-14 at Stade Yves du Manoir on Saturday.
Racing-Metro got off to a great start, and found themselves three points to the good after just four minutes, Gaetan Germain slotting over a penalty.
For a period after that though, the visitors looked on top, as they put pressure on the home defence.
Indeed, they drew level after fifteen minutes, when they had a try disallowed by the video referee, but managed to score a resulting penalty through Delon Armitage.
Racing responded well after that, and took the lead again just five minutes later, another Germain penalty, and they extended their lead further soon after when Josh Matavesi dived over for Metro's second try of the game.
The travelling Exile fans still had hope though, as their team looked dangerous every time they went forward, but Racing added to their lead when Jonathan Wisniewski's delightful drop goal attempt dissected the posts to leave eleven points between the sides.
Irish needed a response, and fast, and they duly delivered two minutes later, when a great Adrian Jarvis chip kick saw Jonathan Spratt race over for a try, Jarvis adding the extras.
The rest of the first half rather petered out, to leave the score 14-10 at the break with all to play for.
The visitors needed a win, and started the second half positively, Jarvis scoring a penalty early on make it a one point game.
Indeed they put themselves in the driving seat soon after, when Joe Ansbro dived over after a great Jarvis pass, with the latter adding the extras from a tight angle.
Irish were now on top, and scored their third try just two minutes later when Adam Thompstone went over, the away side were now in control.
The home side battled to get back in the game, but Irish put the game beyond doubt with seven minutes to go, when Thompstone intercepted a stray Racing pass to secure a bonus point win for the visitors with his second try.
Pen: Germain 2
For London Irish:
Tries: Spratt, Ansbro, Thompstone 2
Con: Jarvis 4
Pen: Armitage, Jarvis
Racing-Metro: 15 Gaetan Germain, 14 Sereli Bobo, 13 Virimi Vakatawa, 12 Josh Matavesi, 11 Juan Imhoff, 10 Juan Martin Hernandez, 9 Mathieu Loree, 8 Jacques Cronje, 7 Bernard Le Roux, 6 Antoine Batut, 5 Jone Qovu Nailiko, 4 Lionel Nallet, 3 Juan Pablo Orlandi, 2 Thomas Bianchin, 1 Julien Brugnaut.
Replacements: 16 Gregory Arganese, 17 Eddy Ben Arous, 18 Johannes Coetzee, 19 Francois van der Merwe, 20 Sebastien Descons, 21 Jonathan Wisniewski, 22 John Leo'o, 23 Sebastien Chabal.
London Irish: 15 Delon Armitage, 14 Topsy Ojo, 13 Joe Ansbro, 12 Jonathan Spratt, 11 Adam Thompstone, 10 Dan Bowden, 9 Darren Allinson, 8 Chris Hala'ufia, 7 Ofisa Treviranus, 6 Declan Danaher, 5 Matthew Garvey, 4 Bryn Evans, 3 Paulica Ion, 2 David Paice, 1 Clarke Dermody.
Replacements: 16 Brian Blaney, 17 Max Lahiff, 18 Faan Rautenbach, 19 Bob Casey, 20 Jamie Gibson, 21 Tom Homer, 22 Adrian Jarvis, 23 Paul Hodgson.
Referee: Nigel Owens (Wales)
Assessor: Bertie Smith (Ireland)