Eddie O'Sullivan admits Ireland fear a confidence-fuelled Wales side ahead of their Triple Crown showdown in Dublin.
O'Sullivan is to go head-to-head with former boss Warren Gatland
Wales, unbeaten in the Six Nations, thrashed Italy 47-8 in Cardiff while the Irish defeated Scotland 34-13 to set up a pivotal 8 March clash.
Irish coach O'Sullivan said: "In 2005 Wales built momentum throughout the tournament and won the Grand Slam.
"All sides play better when they're confident but Wales do fire very well when they're on top of their game."
Wales' stunning win over Italy on Saturday ensures they are the only remaining Grand Slam contenders.
Ireland, on the other hand, recovered from their defeat to France to beat Scotland on Saturday.
New coach Warren Gatland's Welsh revolution began with a famous victory over England.
Gatland's men followed up their Twickenham heroics with success over Scotland and Italy as Wales bid for a second Grand Slam in four years.
O'Sullivan's knows his improving Ireland face a formidable force.
"Wales are a very difficult team to play against when they're confident," said the successor to Gatland as Ireland coach.
"They've had some great results in recent years against the top teams in the world, especially in Cardiff.
"They play well as a confidence team and they're in that frame of mind right now.
"We have to be up front about it, accept they're firing at the moment and believe in what they're doing.
"That makes them a force to be reckoned with."
O'Sullivan, whose Ireland are chasing his third successive Triple Crown, has braced Croke Park for a thriller when attack-minded Wales come to town.
"It could be the match of the tournament," he said.
"Because of the direction we're going and because of our own growing confidence, we could have a cracking game on our hands.
"Both teams like to run and if it's a dry day at Croke Park, it will be all bets are off and a great spectacle."
The Ireland coach may be hyping the impending conflict on the pitch but of equal significance will be the personal duel between the rival coaches.
O'Sullivan controversial succession to Gatland as Ireland coach is an intriguing subplot to an already crunch game and a topic which is set to dominate much of the pre-match talk.
But so far O'Sullivan, who had been Gatland's Ireland assistant, has greeted the Kiwi's achievements for Wales with unreserved praise.
He said: "New coaches have come to Wales and introduced fresh ideas, keeping the players on top of their toes.
"They got off to a good start in the Six Nations, getting two important wins.
"The way Warren is rotating the squad points to a much better spread of talent than Wales had in 2005, when they won the Grand Slam.
"That's evident in the way they've moved selection around yet are still getting results.
"The Welsh team have much more depth than in 2005, but it's a similar style of play they're using."