|ICC World Twenty20 Group B, Colombo|
|Australia 125-3 (15.1 overs) beat Ireland 123-7 (20 overs) by seven wickets|
Shane Watson starred as Australia beat Ireland by seven wickets in the opening World Twenty20 match in Group B.
The all-rounder claimed 3-26 to help limit Ireland to 123-7 at the R Premadasa Stadium in Colombo.
He dismissed Ireland captain William Porterfield with the first ball of the game and removed brothers Niall and Kevin O'Brien in the 15th over.
Dropped on 29, Watson hit 51 off 30 balls, with three sixes, as Australia eased home with 4.5 overs to spare.
A minor wobble aside - Watson and Mike Hussey fell in the same over with victory a near certainty - it represented an impressive start to the tournament for 2010 beaten finalists Australia.
Victory over West Indies in their final group match at this venue on Saturday will secure their place in the Super Eights, while Ireland's hopes of avoiding an early exit depend on how they fare against the Windies on Monday.
Despite winning the toss, Ireland struggled to score freely on a two-paced surface that offered only minimal turn.
Their total - albeit modest - represented something of a recovery after they slipped to 33-4, a collapse initiated when Porterfield hooked his first delivery to Mitchell Starc at fine-leg.
Paul Stirling slashed Starc to a running Watson at third man, Ed Joyce drove tamely to mid-off and Gary Wilson was lbw to 41-year-old Brad Hogg as he aimed to leg.
Ireland were therefore indebted to the O'Briens, who added 52 in seven overs for the fifth wicket.
Kevin was the chief aggressor, taking successive off-side fours off Hogg, but the momentum built up during an over from Starc that cost 12 was punctured when both brothers fell in the following over.
Niall, sweeping, was bowled for 20, and Kevin was caught behind off an attempted uppercut after making 35 off 29 balls.
Alex Cusack and Nigel Jones's late rally, which featured the only six of the innings, did little to inconvenience Australia's pursuit.
Assisted by one over from Boyd Rankin featuring four leg-side wides, Watson and David Warner shared an opening stand of 60 in seven overs.
Warner, who became only the third batsman to score 1,000 runs in Twenty20 internationals, was untroubled until he whipped George Dockrell to deep midwicket to perish for 26.
Watson - dropped by Stirling in his follow-through - responded by heaving the off-spinner and then Dockrell for six, the second of which took him to a 28-ball half-century.
Although Watson was beaten by Trent Johnston's direct hit from short third man and Kevin O'Brien won an lbw verdict against Hussey in the following over, Cameron White and skiper George Bailey eased any nerves that may have existed in the Australia dressing room.