Australia has so far failed to tame the shortest format of the game and it will be a test of their character when they face William Porterfield-led Irish side, who are well known to spring a few surprises at the big stage.
Though, they have just one victory to their credit against an ICC Full Member side in the T20, their unpredictability can well be gouged by a thumping win over England in the 50-over World Cup last year at Bangalore.
Ireland's World Cup triumph over Pakistan in 2007 World Cup in the Caribbean is yet another example of their ability to surprise big teams.
The Irish men have won both their warm-up matches in the build up to the championship and interestingly, they were also briefly ahead of Australia on the ranking list earlier this month, something that Kangaroos will be wary of.
Having lost to minnows Zimbabwe in the same championship in 2007 and being bundled out at the group stage in the 2009 edition, Australia will have a tough task at hands on Wednesday.
"I will only rest easy when that game's (against Ireland) passed," Australia's coach, Mickey Arthur, said.
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"That's not through fear of failure. They have been a giant-killer and they're playing with a quite nice bit of freedom. Any team in this competition can win if they have a good day," he added.
Australia warmed-up for the campaign with a comprehensive win over New Zealand, but their nine-run loss to defending champions England in their second warm-up match, courtesy to some wayward bowling from their speedsters, would be a cause of worry for skipper George Bailey. (MORE)