PNG Hunters players Brandy Peter and Edward Goma featured in the Gurias side that rattled the Vipers who were out of sorts in the first half.
Gurias had the lead early after being awarded two penalties that pushed them to the 10-metre mark.
It was a solid effort by Gurias five-eighth Ase Boas in fending off Vipers fullback Josiah Abavu, before scorin in the second minute.
The Vipers lacked structure and were found jostling among themselves for running space.
Abavu and captain Richard Kambo slowly gave direction to the defending premiers.
Abavu was forced to defend when Gurias prop Jackson Undi crashed into a group of Vipers before offloading to lock Danny Patrick, who punched through a gaping hole, wrestled Abavu and hooker Presley Soto out of his way before slamming the ball beside the posts in the 25th minute. Jason Missian converted to make it 12-0.
Gurias came barking back at the Vipers try line only to have Missian helped off the field after Abavu sailed through the air and caught him awkwardly in a flying tackle.
He suffered a bloodied gash on the forehead.
Missian, along with Vipers halfback Tiliks Kawage suffered minor concussion and bleeding in what was a physical encounter between the two glamour teams.
The Gurias regrouped for another raid after halfback, Watson Boas nailed an impressive 40-20 and later set up a try for Goma to score.
Quentin Ragi converted to lead 18-0.
Vipers replied with a try to Abavu that Soto failed to convert. Gurias led 18-4 at halftime.
The Gurias failed to score again as the Vipers posted two tries, one to Ragi followed by hooker Soto.
Vipers lock Stanley Torato converted both tries to make the scores 16-18.
The Gurias missed aanother try after it was disallowed by the referee.