Tigers hooker Noel Joel grabbed two tries, one in each half, to secure the Morobe side the win.
Conroy Matmilo, Pasu Avani and Justin Olam were the other try-scorers.
Lahanis, with the home crowd behind them, managed to score one try in the first half through debutant Philemon Kimisive.
Seasoned campaigners Felix Tatsim and Francis Takai scored their side’s only points in the second 40.
After a brutal opening set, Eastern Highlander Matmilo crossed for the Lae men following an attacking set. Five-eighth Charlie Simon missed the conversion for the Tigers to take a 4-0 lead.
The Lahanis fought back through experienced trio Micah Soboni, Casey Frank and Supa Kokote, while Ismael Avute, Waisy Joe, Bernard Tatsim and Francis Takai tried hard.
The Tigers’ absorbed the pressure and struck back with a try to Joel, who ran 40-metres untouched to score after he was set up by Bernard Lama.
The Tigers went 10-0 up.
The hosts worked hard to get play deep into Tigers’ territory and winger Kimisive crossed the line following good lead-up work by halfback Frank.
Avute missed the conversion and the Lahanis trailed 4-10 at halftime.
Two staunch Lahanis supporters Members of Parliament Wera Mori (Chuave) and Police Minister Robert Atiayafa (Henganofi) added flavor to Lahanis camp by donating K50,000 each to the team at half time but this match was not going to won with wads of cash but plenty of hard work.
Five minutes into the second half, Joel crossed over for his second try giving his side a comfortable 12-point lead. The Tigers lifted their intensity and kept up the heat on the home side with Avani scoring the try that all but broke the Lahanis resolve. The Lahanis scored a consolation try before full time after Kimisive set up fullback Takai for an unconverted try.