Vipers scored all their 28 points in the first half with tries to Manu Soli, William Tirang, John Stanley and Peter Mondo, Yunny Patrick kicked 4 goals from 5 attempts.
Isou's first points came from a converted try by Jerry Teme just before halftime.
After the break, Isou came out of the tunnel showing a lot of resilience in the 2nd half to score two tries in back to back fashion through Woods Kawage and Teme, while David Joseph’s 3 from 3 kick cut down the deficit by 10 points at 18-28 Vipers.