The England World Cup star spearheaded an Irish points blitz at Rodney Parade as Irish led 24-0 inside 20 minutes, ruthlessly ending this Pool One encounter as a meaningful contest.

Wing Tomas De Vedia pounced for two early touchdowns as the Dragons' defence was blown apart with ridiculous ease, then fly-half Catt and centre Delon Armitage added further scores to confirm Irish's first Heineken Cup away win at the seventh attempt.

They have a maximum 10-point return heading into next month's trip to group favourites Perpignan and the quarter-finals are unquestionably a realistic target.

The Dragons though, are virtually out of contention, and it could take them a while to recover from the physical and mental scarring inflicted by a superior Irish side.

They suffered a record home defeat in the competition, eclipsing a 38-11 loss to Sale Sharks in 2005, courtesy of Armitage adding his second touchdown - an interception effort - seconds from time.

A consolation Michael Owen try scarcely lifted the Dragons' sense of gloom, with Owen's opposite number Nick Kennedy opening six-try Irish's second-half account, while immaculate full-back Peter Hewat added 15 points from the boot.

The Dragons, buoyed by a losing bonus point collected in Perpignan last week, saw Wales' 2005 6 Nations Grand Slam full-back Kevin Morgan return after knee surgery, while flanker Jamie Ringer replaced neck injury victim Dan Lydiate.

Irish made a solitary switch after their bonus point success against Treviso, handing Samoan Sailosi Tagicakibau a start on the left wing instead of Topsy Ojo.

The Dragons should have struck first when they sliced open Irish's defence on four minutes through quality approach play by centre Rhodri Gomer-Davies and hooker Jones, but lock Luke Charteris could not finish off.

Watching Wales caretaker coach Nigel Davies would have been impressed by such a lively opening - but it soon became a nightmare for the home side.

Hewat slotted a penalty, then De Vedia completed a crisp move sparked by Catt's charge deep into Dragons territory.

Trailing by 10 points in as many minutes, the Dragons' shellshocked appearance encouraged Irish to capitalise, and De Vedia prospered from defensive hesitancy to claim another score.

Then it was Catt's return to scamper clear before Armitage powered over after a Ceri Sweeney penalty, making it 31-3.

Owen claimed a close-range touchdown as half-time approached, converted by Sweeney, but the Dragons had been out-muscled, out-witted and out-paced during a hopelessly one-sided encounter.

The second period was all about damage-limitation from a Dragons perspective, but it took Irish just eight minutes of the second period to increase their lead.

Centre Seilala Mapusua powered deep into the Dragons half, before Tagicakibau gathered his pass and then off-loaded brilliantly to a supporting Kennedy.

Hewat's fifth successful conversion inched Irish close to 40 points with almost 30 minutes remaining, which was the cue for Catt's departure - his job done - to be replaced by Paul Hodgson.

The Dragons managed a second touchdown late on, hooker Steve Jones ploughing over from close range, but although Sweeney added the extras, nothing could disguise an emphatic Irish display that augers well for tougher challenges ahead.

But after the Ospreys' defeat at Gloucester, it looks like being another long, painful struggle for Wales' regional sides in Europe this season.