In the 19th minute, right wing back Kohei Matsumoto made it 2-0 after defensive midfielder Nile Walwyn deftly pirouetted before turning defence into attack in the middle of the field.
From the ensuing passage of play left wingback Fergus Neil curled the ball across the face of the goalmouth and Matsumoto became the beneficiary on the far post after a swag of players from both sides missed the cross.
It was Barbero again in the 32nd minute, dutifully following up to make it 3-0 after Waitakere goalkeeper Pirmin Strasser's sliding body deflected a Sam Mason-Smith shot with no defenders within reach to put it out of harm's way.
The hosts maintained their lead into the breather and should have scored more goals had they polished their boots.
In the 47th minute, Waitakere United midfielder Ryan Tinsley was stretchered off after a tackle from Neil, who got a yelloew card for his troubles from referee John Rowbury as play was held up for about five minutes.
Midway in the second spell, St John Ambulance staff gave Tinsley some laughing gas and pain killers as he sat on a chair at the entrance to the main stand nursing his left leg.
They wheeled him away on a stretcher for a suspected fracture of the fibia, according to to a team official.