|Grenoble (9) 15|
|Pens: Hart 5|
|London Irish (17) 25|
|Tries: Mulchrone, Aulika, Lewington, Narraway Con: Geraghty Pen: Noakes|
London Irish made it two wins from two in the European Challenge Cup with a bonus-point victory against Grenoble.
Fergus Mulchrone, Halani Aulika and Alex Lewington all crossed in the first half as the Exiles took a 17-9 lead.
The French side were in touch for much of the game, with Ireland-born James Hart kicking five penalties.
But Chris Noakes landed a penalty of his own and Luke Narraway's second-half try earned a bonus point, leaving Brian Smith's side top of Pool One.
|London Irish: Remaining Pool One fixtures|
|6 December: Cardiff Blues (a)|
|13 December: Cardiff Blues (h)|
|17 January: Grenoble (h)|
|24 January: Rovigo (a)|
London Irish ran in 10 tries in a convincing victory over Rovigo in their opening group match.
Director of rugby Smith recalled a number of first-choice players to his starting XV and although scrum-half Hart kicked the first points of the match for Grenoble, the visitors were soon in front.
Centre Mulchrone touched down in the corner for their first try, and shortly after Grenoble winger Daniel Kilioni had been yellow-carded, a powerful drive from the forward pack sent Tonga international prop Aulika over.
Lewington added a third for London Irish before half-time but Hart's efforts with the boot either side of the interval allowed the home side to maintain a manageable deficit.
Fly-half Noakes extended the lead to five points, despite the Exiles being down to 14 men with lock Jebb Sinclair in the sin bin. After his return to the field, back-rower Narraway went over with 15 minutes left to secure victory.
Grenoble: Aplon; Mignot, Willison, Messina, Kilioni; Michalet, Hart; Hugues, Bouchet, Choirat; Rey, Skeate; Vanderglas, Marrou, Hayes.
Replacements: Jammes, Coulson, Buckle, Roodt, Alexandre, Saseras, Gengenbacher, Caire.
Sin-bin: Kilioni (14).
London Irish: Fenby; Lewington, Mulchrone, Geraghty, Short; Noakes, O'Leary; Court, Paice, Aulika; Low, Sinclair; Narraway, Cowan, Treviranus.
Replacements: Stevens, Parr, Halavatau, Leo, Gilsenan, Allinson, Griffin, Ojo.
Sin-bin: Sinclair (53).
Referee: Peter Fitzgibbon (Ireland).