ANDY BALBIRNIE has announced his arrival as an international batsman with two half-centuries in the past week but, despite his superb 97 against Zimbabwe on Saturday, Ireland are now favourites to depart the World Cup in the cruellest way - on run-rate.

Narrow wins like the nail-biting five-run success in Hobart may be great entertainment and prove yet again that Ireland belong on the world stage but they are as damaging to the all-important net run-rate as they are to the nerves of fans watching.

Entering the final week of Pool B matches, Ireland have to beat (or tie with) India in Napier tomorrow or Pakistan in their final game in Adelaide next Sunday to reach the quarter-finals. An abandonment of either game would also suffice.

Two defeats, allied to an expected victory for the West Indies over the United Arab Emirates, would see the Boys in Green finish equal fourth with the Caribbean team but with a far inferior net run-rate.

India should prove the tougher of Ireland's two assignments but the defending champions may not be quite as focused after South Africa's loss to Pakistan on Saturday meant MS Dhoni's unbeaten team are almost certain to top Pool B.

"India are a strong team all-round - they're world champions for a reason - but we're going up against them with nothing to lose and we want to play some good cricket," Balbirnie said. "I personally can't wait to get out there and score some more runs."

Promoted to No 4 on the back of his half-century against South Africa, Balbirnie helped centurion Ed Joyce add 138 for the third wicket against Zimbabwe which was the meat of a mighty 331-8 - Ireland's best World Cup score, but only just enough runs to secure victory.

"Getting the fifty against South Africa did give me a lot of confidence but I am aware it's only two knocks and I haven't done anything major. I just want to keep on scoring runs and hopefully contribute to another win or two in these next two games," Balbirnie said.

The Pembroke and Middlesex right-hander was denied a deserved century when, at the start of the final over, he called George Dockrell for a second run that wasn't there.

As Ireland spent the day travelling from Hobart back to New Zealand for a second time, Kevin O'Brien's fastest World Cup century record, from 50 balls, came under threat from Glenn Maxwell as Australia beat Sri Lanka by 64 runs.

The in-form Aussie charged to 96 from 47 deliveries but after taking two more balls to reach 99 Maxwell's honesty cost him a share of the record when he confirmed to the umpire that what the crowd thought was his 100th run was indeed a leg-bye.

Maxwell, who reached his century from 51 balls, was out for 102 as Australia piled up 376-8.