Mosgiel won on the road, while Green Island suffered its first loss of the season in the Southern Premier League on Saturday.
Mosgiel took an early lead when Kasim Ali struck a thunderous volley from 35m that cannoned off the woodwork, giving goalkeeper Aaron Molloy no chance.
Despite playing into a strong head wind, Wanaka played structured football, with Fletcher Cavanagh and Adam Hewson threatening with direct and skilful runs.
Mosgiel’s Matt Kelly thought he would double the lead when he followed up Lewis Wall’s shot that was parried away by Molloy, but it was ruled out for offside.
Mosgiel got its second soon after in the 23rd minute when Cam Anderson was fouled in the box and Anderson stepped up and sent Malloy the wrong way.
Wanaka reduced the deficit on the half hour when Steve Pleskun turned his marker and his well-placed shot gave keeper Liam Whittaker no chance.
With the interval fast approaching, a jinking run down the byline from Seb Hickman put him in position to deliver a square ball across the box, allowing Anderson a simple tap in.
Early in the second half, Anderson thought he had got his hat-trick, but the goal was ruled out for off side.
Wanaka fullback Levi Fletcher was getting forward at every opportunity and linking well with Barry Grehan. This presented long-range shooting chances to both Hewson and Pleskun which forced Whittaker into action.
With 20 minutes left, Kasim Ali struck a powerful left-footed free kick from the edge of the box to make it 4-1.
Wanaka's Fletcher made another forward run and after winning the ball back he passed to Pleskun who found the back of the net with eight minutes to play.
Champion Green Island dropped its first points in a 6-1 defeat to University.
Queenstown beat Technical 4-1 and Caversham held out 4-3 over Roslyn.
In the Women’s Premier League, Dunedin Technical won an eighth consecutive title with a win over Queenstown, remaining unbeaten throughout the season.
- Neville Watson
