The Irish were tipped to sweep all before them in 2005 but after a promising start they collapsed to successive defeats against France and Wales.

They wilted under the burden of expectation on the last day of the championship at the Millennium Stadium as Wales romped to their first Grand Slam in 27 years.

On Sunday last season's Triple Crown winners return to the scene of that 32-20 mauling with a tricky opener that could silence talk of a clean sleep at the earliest possible opportunity.

But O'Sullivan is confident Ireland have matured into a formidable outfit capable of vindicating the praise showered on them following their success in the November internationals.

'This is a better Irish team on a number of fronts. If everyone is healthy, we now have a deeper squad,' said the Ireland coach.

'There's a lot more maturity in key positions, there's more leadership on the field and there's also a better sense of what we're trying to do as a team.

'Two years on we're a more skilful side. If you analyse all of that, we are a better team than in 2005.'

However, O'Sullivan insists Ireland's recent progress is meaningless without tangible success.

'What goes with improving is actually producing,' he said.

'We must live up to the billing that we are more skilful and more experienced, that we are better players and do have greater depth.

'It's about bringing that to bear on the championship. That's the key.'

Ireland's success in the autumn, when they toppled South Africa and Australia in emphatic style, indicated they are now at ease with the favourites tag.

The demise of their title hopes two years ago taught a lesson that O'Sullivan believes will prove invaluable over the next two months - namely that there is no margin for error.

'I remember losing to France and it was very tight - it turned on a couple of moments,' he said.

'There was a penalty at a ruck which was very harsh and that put them two scores ahead, then a line-break from a set-piece and suddenly the Grand Slam is gone.

'In Cardiff, we just didn't play well. We were missing Gordon D'Arcy that year which was a big loss and Wales were in form. So we finished third and it was disappointing.