The two teams were tied at the foot of the table on six points before the round and both were keen to seal victory.
After a scoreless first half, Green Island took control just three minutes after the restart when Weston Bell’s cross was slotted home by Harrison McClean.
The second goal came not long after when Trevin Myers turned on halfway, spotted the keeper off his line and hit an immaculate strike over the keeper into the net.
Green Island conceded a penalty after a clumsy challenge from Stefan Milidrag. However, it was saved by Benoit Beaujeon then blasted wide on the rebound by the taker.
Milidrag completed victory with his goal in the 88th minute.
The Dunedin City Royals, seeking to stay on the tail of leaders Christchurch United and Cashmere Technical, were held to a 1-1 draw at home by Selwyn.
It looked like the Royals would blow their opposition away on a windy pitch with fullback Sean Cooper getting forward, linking well with Ollie Petersen and allowing Ben Stanley and Tyler Muir plenty of scoring opportunities.
The home side’s dominance finally told in the 42nd minute when Ben Stanley’s attempt on goal was blocked, but a penalty was subsequently awarded when Petersen was fouled.
Connor Neill struck the spot kick low and to his right, giving keeper Pieter Bierema no chance.
A needless foul by Hayden Aish early in the second half gave Selwyn a free kick, and the ball was only partially cleared out to Luke Mackay, who from 30m struck a sublime shot into the top-right corner to equalise.
The Royals had a chance to regain the lead when Bierema lost the ball and Will Turner nearly headed home.
As the second half continued, the Royals were struggling to break through Selwyn’s defensive block and goalkeeper Alex Boomer was called into action to save a goal-bound drive.
With time nearly up, Josh McCarroll saw his shot go wide of the post. Muir then burst into the penalty box and was about to shoot for goal but he was denied the winner by a superbly timed tackle.
In the ODT Southern Premiership, Mosgiel and Roslyn remain unbeaten at the summit of the table.
Mosgiel beat Northern 4-2 after first-half goals from Rory Findlay and Luke Clissold.
Northern pulled it back to 2-2 with goals a minute either side of halftime to Al Julanda Al Mawali and Johnny Woodall.
Dean Allan’s own goal restored the Plainsmen’s lead and Clissold made sure of all the points with the fourth goal after 69 minutes.
Roslyn beat Wanaka 2-1 at Ellis Park. Both Roslyn goals came in the first half, through Mitchell Gray and Callum Smith, and Daniel Brum pulled one back for Wanaka.
The two sides will clash again next weekend at the same venue in the fourth round of the Chatham Cup.
Queens Park came back from being 2-0 down against Green Island after 23 minutes to record a 4-2 victory.
University beat the Dunedin City Royals 5-3, and Bailey Chambers bagged his ninth goal of the season with a stoppage-time equaliser to secure Northern Hearts a 1-1 draw in Queenstown, which had led with a Thomas Mills goal.
— Neville Watson