After a six month deployment with the Navy, Thirroul debutant Stephen Holmes helped sink two-time Illawarra Touch Premier League champions Helensburgh.
Holmes first touch produced a length of the field runaway try to put the Butchers ahead at half-time, before they dominated the second half to claim a 10-4 victory.
It came after two draws this season, Thirroul are one of three teams still unbeaten.
"It was great to get the monkey off the back with our first win," captain Jared Constable said.
"Even though the Tigers were down on troops and far from full strength.
"We still made a few silly mistakes in defence, but we know where we can improve and we'll keep building as the season progresses."
A depleted Stingrays of Shellharbour also remained unbeaten with a 7-7 draw against West's, and Corrimal are still without loss taking down Dapto 6-4.
In the women's league, Gerringong thrashed Corrimal 10-2, while Jamberoo crushed Albion Park 14-1 and Woonona beat Stingrays 5-1.