Papakura scored first in the second spell - "that gave us a bit of a fright" - but the visitors got back on top and pinched a fourth goal for a comfortable win.
Davis said his standout players were the three up front - Mitchell Miller, Alexis Pinto and Harlem Simiona.
The goal scorers were Miller (his seventh of the season), Pinto, Alan Ferguson and Josh O'Sullivan.
Davis said the three points would give his young side great confidence going into next week's home match with league leaders Fencibles United from Auckland.
Ngongotaha now sit second from bottom on the table with one win and three draws from their six matches.
Meanwhile, in the Loaded WaiBOP Premiership on Saturday Taupo AFC beat Rotorua United AFC 2-1 at Neil Hunt Park.