The match-winner came from midfielder Ilagi Geno in the 114th minute in front of a packed Sir Ignatius Kilage Stadium.
It was a fast flowing game and both sides had nearly equal opportunities to get on the board early in the encounter.
It seemed likely it would be a scoreless first half, but a handball in the penalty box presented Erema the opportunity to break the deadlock.
Captain, Pakot Poesi made sure of it whizzing it past the keeper to take Erema to a 1-0 lead at half-time.
The stadium erupted in celebration eight minutes into the second half when Eliud Fugre headed the ball into the nets to equalize.
But the celebration was short lived after an own goal put Welgris behind on the scoreboard again.
With the crowd behind them, Welgris lifted and in the 75th were rewarded for their persistence through a perfectly timed cross that found the boot of Joshua Oscar.
The score was left at 2-2 at full time forcing the match into extra time.
Goals to both teams in the first half left them tied up again at 3-3.
But Gulf Erema proved they wanted the title more than anything else with the 29 year old Geno from Papaka village slotting through what was the winner.
From then on, it was all defence as Erema held on to come out victors.