LONDON, Feb 6 (Reuters) - If the identity of the 2005 Six Nations champions was unclear going into the tournament it was positively opaque after an opening weekend short on quality but high on suspense, nervous tension and late drama.

When the dust settled, Ireland, Wales and champions France were left with a tick in the wins column, Scotland and Italy could take much from defeat leaving only world champions England with that empty feeling.

The action began in Paris on Saturday with Scotland, who failed to muster a point last year, pushing France all the way before a controversial refereeing decision and a late try gave the hosts a flattering 16-9 victory.

Wales picked up the baton of the underdog to dominate England in an extraordinary atmosphere in Cardiff, deservedly claiming an 11-9 success for their first win over the world champions in the city for 12 years.

The pattern continued on Sunday in Rome where Italy produced one of their best-ever championship performances only for two moments of Brian O’Driscoll magic to push Ireland to a 28-17 success.

The victory came at a price for the Irish, however, as they lost O’Driscoll and his centre partner Gordon D’Arcy to hamstring injuries that make both men a doubt for next week’s trip to Scotland.

Ireland will travel to Edinburgh still on course for their first title in 20 years but they will need to show considerable improvement if they are to achieve it.

They started sluggishly in Rome, were pinned in their own half for long periods and were overpowered up front.

Two typically evasive runs by O’Driscoll saved them, setting up tries for Geordan Murphy and Peter Stringer, while Denis Hickie added a third close to the end.

Prop Martin Castrogiovanni scored Italy’s late try after fullback Roland de Marigny had kept them in the game with three penalties after Luciano Orquera had missed three out of four.

It was a creditable defeat for John Kirwan’s team, as it was for Scotland, though their Australian coach Matt Williams was left fuming by a touch judge’s ruling 12 minutes from time that cancelled out a try by number eight Allister Hogg for stepping into touch.

"We didn’t deserve to be robbed blind like that. It was terrible, terrible decisions that cost us the game," said Williams.

France were level at that stage at 9-9, having trailed for most of the match, and clinched it with two minutes remaining when Damien Traille charged down a Hugo Southwell clearance kick and touched down.

"We didn’t try anything, we were in a very uncomfortable position, we lacked possession and when we won the ball we dropped it," France coach Bernard Laporte said.

It was party time in Cardiff after Wales’s nerve-jangling win over old enemies England sent the nation into collective delirium.

Mercurial centre Gavin Henson lived up to his billing by winning the match with a 40-metre penalty four minutes from time.

Wales scored the only try, through winger Shane Williams in the 10th minute, and should have been away and clear of an England team who just failed to click.

As it was, Charlie Hodgson’s third penalty had England 9-8 up with 10 minutes remaining but, after a series of narrow defeats, this time Wales finished on top.

"It was brilliant, everything you want to be a part of," said coach Mike Ruddock, taking charge in the Six Nations for the first time.

Wales travel to Italy next week while England must regroup before facing France at Twickenham followed by the tough trip to Dublin.

Saturday’s defeat was their seventh in the 12 games they have played since winning the World Cup and the likes of Martin Johnson, Lawrence Dallaglio and Jonny Wilkinson are proving predictably difficult to replace.