The win followed a similar strong home ground performance against the Gulf Isapea last Sunday, where a Wera Mori pep talk woke the Eastern Highlanders from a sluggish opening 40 to race home 30-8 winners.
Against the Leonard Tarum-coached Vipers, the Lahanis scored five tries and kicked a field goal to bag their second win on the trot.
The capital city men have been on the improve since their embarrassing pair of defeats to the Tigers (48-0) and the Isapea (16-8) in the consecutive weeks.
The Vipers showed they meant business when centre Ben Wemin crashed over for the first try.
Halfback Quinten Ragi added the extras and the Lahanis fans watched on as the visitors took a 6-0 lead.
But the excitement subsided when the home side replied with a try to full-back Francis Takai.
Felix Tatsim levelled the score with a successful conversion.
Takai proved a slippery customer bagging his second try a short while later and a successful conversion by Tatsim saw the Lahanis move out to a 12-6 lead by the 21st minute.
Lahanis lock Bernard Tatsim Jr proved a handful for the Vipers defence when he barged his way over for another four-pointer.
The Vipers’ class began to shine through as they tightened up their game and started to apply pressure on the Lahanis in their own half.
Results: Northwestern Pool – Simbu Lions 10 Enga Mioks 4, Mendi Muruks 14 Waghi Tumbe 16, Hagen Eagles 14 Hela Wigmen 18; Eastern Pool – Goroka Lahanis 31 Port Moresby Vipers 24, Tigers 28 Gulf Isapea 14. Bye: Gurias. The National