London Welsh's hopes of making the knockout stages of the Challenge Cup took a knock with defeat by Grenoble.
The scores were level at half time as Clement Darbo's two successful penalty attempts were matched by a couple of kicks by Welsh's Alex Davies.
The fly-half booted Welsh ahead after break but Vincent Campo's 50th-minute converted try put the hosts in control.
Davies missed two further kicks and Andrew Farley's late try ensured victory with Nick Runciman sin-binned.
The result at Stade Lesdiguieres leaves London Welsh in third place in pool five, five points adrift of second placed Stade Francais and just one win from three games.
Victory takes Grenoble to the top of the pool, although they are likely to be usurped when Stade play group minnows Cavalieri on Saturday.
Grenoble: Tuculet; Waqaseduadua, Jaouher, Butonidualevu, Ninard; Hart, Darbo; David, Campo; Rey, Farley; Alexandre, Best, Nouhaillaguet.
Replacements: Fabro (for David 51), Hegarty (for Campo 54), Pollard (for Ray 61), Stewart (for Darbo 66)
London Welsh: Arscott; MacKenzie, Lewis, Jewell, Smith; Davies, Runciman; Bristow, Bateman, Joly; Brown, Corker; Beach, Hills, To'oala.
Replacements: Hafu, Moss (for Bristow 68), Tideswell (for Joly 63), Mills, Denbee, Keyte, Whatling, Scott.