The reigning champions, gunning for an unprecedented third straight title, pulled two points clear of their rivals with a comprehensive nine-wicket victory which also inflated their net run rate considerably.
Ireland captain Trent Johnston admitted his giantkillers had “let down the fans”.
Having exceeded expectations by beating Pakistan to reach the second stage of the World Cup and stayed relatively competitive in the other Super Eight matches, his side were emphatically beaten at the Kensington Oval.
Put in to bat, Ireland were dismissed for a lowly 91 — the ninth lowest total in World Cup history — with man of the match Glenn McGrath claiming three for 17 and Australia wrapped up their triumph in only 12.2 overs in reply.
They were watched by a strong contingent of the Blarney Army and Johnston conceded: “We don’t want to disappoint the fans because a lot of people have travelled from Ireland to watch these two games and we were disappointing today and let them down. We’re going to go out there in the next game against Bangladesh and firstly play for ourselves and secondly play for them because they’ve been fantastic.
“It’s been the one thing that’s guided us through this World Cup, especially the group stages in Jamaica.
“If we can do well in the next game, hopefully we can send them home happy again.
“It’s disappointing because there would have been people watching this back in Ireland and seeing us not putting up such a good show as we have in the previous games.”
Johnston stressed: “We were outclassed by a better team, you don’t have to be Einstein to work that out.
“It’s unfortunate because we set out to be competitive today and it didn’t turn out that way and that’s why they’ve been the best team in the world for the last 10 years.
“They bowl good areas, tied us up and we got out. Our top order didn’t come to the party and it’s pretty difficult when your top four batsman get two runs between them.”
Despite now having no chance of qualifying for the semi-finals, Ireland still have two games left and Johnston hopes to record a first Super Eight victory over Bangladesh in their next game.
“We’ve still got a bit of cricket left in us yet,” he said.
“They’ve got some form with the ball. They recently beat South Africa so we’re not going to take them lightly at all.”
Glenn McGrath’s three wickets take his haul for the tournament to 18 and established him as the leading wicket-taker in the competition.
But he had little sympathy for the Irish part-timers, adding: “When we play well there are not too many teams in the world that can beat us and Ireland probably aren’t up to the standard of other teams.
“It was always going to be a tough day for them. Unfortunately for the spectators and viewers, the game was cut by half.
“Taking wickets is good for the confidence and it shows how well the team is playing that our top three bowlers are in the top six or seven wicket-takers in the tournament.”
Australia captain Ricky Ponting was pleased with his side’s professionalism, saying: “It was a good performance today. It was nice to win the toss and make use of a pretty lively wicket early on.
“We’ve achieved what we’ve wanted to achieve so far in this tournament, especially out of today’s game.”
Ponting is unsurprised Australia have put together 19 straight World Cup wins and is looking forward to tough examinations in their final two Super Eight games.
“I think we’ve got a good record over the years of stringing together consecutive wins, whether it be Test matches or one-day internationals,” he said.
“We’ve got two very big games, two very good teams Sri Lanka and New Zealand coming up.
“It’s really the business end of the World Cup now.”