Ireland's World Cup win over West Indies surpassed their toppling of England four years ago and will make their Pool B rivals "very nervous", according to Graeme Swann.
Ireland chased 305 to beat the Windies by four wickets with 25 balls left in their opening match in Nelson.
"This is a better victory than the one against England four years ago," said former England spinner Swann.
"That was a one-man show from Kevin O'Brien. This was a team effort."
|Ireland's love of the chase|
|It is the fifth successful World Cup chase in excess of 300 and three of them have been by Ireland|
|Ireland's 45.5 overs was the sixth quickest of all successful ODI run-chases of 300 or more|
|John Mooney, just as he did against England four years ago, struck the winning runs|
At the 2011 Word Cup in Bangalore, facing an England side including Swann, O'Brien cracked the fastest World Cup century as Ireland recovered from 111-5 and overhauled their opponent's total of 327-8 with five balls to spare.
Four years on, the Windies' 304-7 was almost as imposing, but half-centuries from Paul Stirling, Ed Joyce and Niall O'Brien saw Ireland cruise to their target.
"This was five or six people putting their hands up and delivering an absolutely world-class performance," added Swann on BBC Test Match Special.
The other teams in Ireland's group are holders India, South Africa, Zimbabwe, Pakistan - who Ireland shocked in 2007 - and their next opponents, United Arab Emirates. The top four will reach the quarter-finals.
"On this performance, they can certainly look to get out of the group," said Swann.
"They will still be underdogs when they play bigger teams but they have destroyed West Indies and every other so-called big team in the group will have watched this and will be very nervous about them now."
Ireland captain Will Porterfield said the team are aiming for the knockout stages after their latest victory over a Test-playing nation.
"It's fantastic to win. This sets us up nicely for the next few games," he said.
"The belief has been growing within the squad for a long time and we know what we are capable of, not just in this game but the other games in the competition as well."
The defeat is the latest blow to West Indies, who won the first two World Cups in 1975 and 1979 but are now ranked eighth in the one-day standings.
The latest pay dispute between players and the West Indies Cricket Board led to the abandonment of October's tour of India and the controversial omissions of Dwayne Bravo and Kieron Pollard from their World Cup squad.
Under the leadership of rookie captain Jason Holder, West Indies looked disjointed and demoralised against the Irish.
"Their body language worries me more than anything else," added Swann. "From ball one if they beat the bat there was no clapping and cajoling. When they took wickets there was no excitement or energy.
"From an outsider's point of view there is being cool and laid back, and there is being a fractured team, and the West Indies really do look fractured and disenchanted at the minute."