Cardiff kept their European hopes alive with a thrilling victory at the Arms Park, hauling back Pool 5 leaders Montferrand to within a point.

The Blue and Blacks' two-try hero was full-back Rhys Williams, whose horrendous errors had proved catastrophic in the away leg in France.

After Iestyn Harris kicked the home side into an eighth-minute lead, the game settled into attritional warfare, lit up by searing breaks from Montferrand backs Tony Marsh and David Bory.

Centre Jamie Robinson's grubber kick was perfectly weighted but escaped the hands of the chasing Matt Allen and Anthony Sullivan.

Cardiff had to settle for another Harris penalty to reward their pressure, but French fly-half Gerald Merceron responded in kind for the visitors.

Williams brought a flash of inspiration to a scrappy game when he collected from Rob Howley on halfway, kicked ahead and won the race for the line.

Harris converted, but Merceron narrowed the gap with penalties either side of the break.

Harris stepped up with two more successful kicks - passing 100 points in seven games for Cardiff in the process - but crucially missed two, while his opposite number landed another two.