Sam Warburton, captain of the Welsh side, says recent setbacks has not dimmed Wales' confidence at the Six Nations.
Six Nations Rugby: Wales is confident as Ireland await in opener
Sam Warburton, the Wales captain, said he and his teammates will take "massive confidence" from their status as reigning Six Nations champions as they aim to end a demoralising losing run on Saturday.
Wales have not beaten another Test-playing country since defeating France to secure last season's Six Nations title and a third Grand Slam in eight years.
Losses against Australia (four times), New Zealand, Argentina and Samoa mean that Wales are experiencing their most barren run for nine years and go into this season's tournament as fourth favourites behind France, England and Ireland.
The Irish are first up at the Millennium Stadium in Cardiff, a reversal of last year's opening fixture at Dublin when Wales prevailed thanks to full-back Leigh Halfpenny's late penalty strike.
Despite a lengthy injury list that currently includes the likes of Ryan Jones, Rhys Priestland, Richard Hibbard, Alun-Wyn Jones, Luke Charteris and Bradley Davies - plus head coach Warren Gatland's absence due to British and Irish Lions commitments - Warburton remains in upbeat mood.
"We were not favourites last year, but as players you ignore it," he said.
"No-one really knows what is going to happen until the first weekend of rugby. After it, we will have a much better idea of how teams are shaping up.
"We will take massive confidence from going into the game as defending Grand Slam champions. Regardless of what has happened since then, you cannot take that away from us.
"It was a great achievement and a lot of the boys from last year are here and know what it takes. The young players can let the negatives go over their heads and not affect them.
"It is a very confident camp, and I am always the optimist."
Saturday's other game sees England take on Scotland at Twickenham, with the visitors having not won there since 1983.
Stuart Lancaster, the England coach, wants his side to be come more consistent in his second full year in charge after a first 12 months that was highlighted by a victory over world champions New Zealand in November.
"It is important. To win consistently is important. That is what champion teams do," he said.
"Expectations have risen and this time last year people were looking at us as an unknown force. Now they know.
"The trick is to win consistently, even when you are the target. That is what the All Blacks do."
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