Hard-running Willie Whakatau was rewarded with a try, making it 20-6 with eight minutes of the half to go.
Kapua's hard work was rewarded right on the hooter and, at 20-12 at the interval there was hope of a Chiefs comeback.
However, Pikiao started the second half like they did the first, with King getting his second try and then Rocky Ahuriri scoring to make it 28-12.
While Ngongotaha had their moments and neither side was prepared to back out of the collisions, it was the Warriors who gradually put a stranglehold on the game, surviving being reduced to 12 when Ahuriri was sin-binned with 15 minutes on the clock.
Warriors coach Henry Lingman was happy with the two points, but not totally comfortable with the performance.
"It was scrappy - they went totally away from the game plan and tried to muscle them up and tried to play them at their own game," he said. "They started off good and got 10 points up, but that's when they went away from it."
The result was too many dropped balls and too many defensive lapses.
"Don't get me wrong, I'm happy because it was our first win for the year and it gets us back on track."
Hooker Green was Lingman's pick for his player of the day.
After two big losses, Chief's coach Joe Taute said it was one of the better performances.
"They stuck together and it's something we can build on. Some of the guys, it was their first game so I am happy with their efforts. But it's fair to say we need to get them better and stronger and more skilful."
Next weekend the Chiefs travel to Taupo while Pikiao host Otumoetai Eels.
Cross Country Rentals Waicoa-Bay Premiership results:
Premier Grade:
Turangawaewae 10 Hamilton City Tigers 34, Ngongotaha Chiefs 26 Pikiao Warriors 52, United 28 Taupo Phoenix 34, Taniwharau 21 Pacific Sharks 28. Otumoetai Eels - bye
Reserve Grade:
Turangawaewae 10 Hamilton City Tigers 36, Central Lions 58 Pikiao Warriors 30, United 46 Reporoa Razorbacks 28, Taniwharau 30 Pacific Sharks 30. Otumoetai Eels - bye.
BOP/Coastline Division 1:
Taneatua Warriors 52 Tauhara Te Maunga 10, Mangakino Hawks 54 Putauaki Stags 20, Papamoa Bulldogs - bye.