John Mooney's man-of-the-match spell set Ireland on their way to a resounding seven-wickets win over Namibia at Stormont in Group A.

With Irish skipper William Porterfield having won the toss and having asked the Namibians to bat in damp and overcast conditions, Mooney replaced Tyrone Kane at the ground's City End in the third over of the innings and soon reduced the African side to 45 for 3.

The dangerous Stephen Baard was caught at third man by Niall O'Brien, the veteran Gerry Snyman was caught behind by Gary Wilson, and Raymond van Schoor had his off-stump uprooted by a pinpoint yorker.

Even when Mooney finished his spell (4-0-23-3), returning his best figures in Twenty20 internationals, there was no let-up for the Namibians: Paul Stirling and George Dockrell bowled in tandem, the Irish spinners claiming 3 for 35 in their eight combined overs.

A few lusty blows from the Namibian lower order - including two sixes from JJ Smit (21) and one mighty shot onto the pavilion roof by Jason Davidson - took their team to a final total of 124-8, but this was never likely to be enough.

Only Smit passed 20 for the Namibians, who failed to rotate the strike against the slow bowlers and who therefore played out an incredible 66 dot balls during their twenty overs.

In reply, the Irish cruised home. Despite losing Stirling in the first over, caught at cover pushing forward to Davidson, a partnership of 71 between Niall O'Brien and William Porterfield - batting at the unusual position of number three - broke the back of the chase. How the Namibians must rue dropping both batsmen when in single figures.

O'Brien, who used his feet repeatedly to the seamers, was eventually caught at long-off for 45 (40 deliveries, 3 fours and 1 six) and his brother Kevin fell in the same position, leaving Ireland at 80 for 3 in the twelfth over, but a second major stand saw the hosts home.

Skipper Porterfield - who drove, cut, and pulled with authority - and Andrew Balbirnie put on an unbeaten 48 for the fourth wicket in only 34 balls as the Irish reached their target with 16 deliveries to spare.

Porterfield struck the first ball of the eighteenth over past extra cover to bring up his half-century and repeated the shot the next ball to secure victory for the hosts. He finished on 56 (44 balls, 7 fours and a six), while Balbirnie remained unbeaten on 18 from 14 deliveries.

This was a clinical and professional all-round performance from the Irish, who next face the USA on Sunday, while Namibia play Nepal tomorrow afternoon.