"They had big men who kept knocking so we kept shutting the door on them to send them back home, so I'm very proud of my boys," Greatholder said.
"We couldn't trust ourselves to play a passing game. It's not always about playing a game with pretty, little passes."
The visitors broke the deadlock in the 71st minute when American import Sean Morris found the net after substitute Nathaniel Hailemariam made an incisive run down the left flank before squaring the ball to Morris who slipped the ball past a WaiBOP defender and goalkeeper Andrew McNeil.
Just as Hailemariam showed promise off the bench in Bay United's 4-2 victory in the first game of the ASB Premiership in Napier the previous Saturday, the versatile forward again didn't disappoint as a super sub.
"If I can say it was an inspired sub from the coach and Natty [Hailemariam] made an immediate impact," Greatholder said with a laugh.
The energy-sapping, don't-argue 2-0 came in the 86th minute when Morris quickly took a short corner with Tom Biss, who deftly crossed the ball to striker Tomas Mosquera to nod the ball into the net past keeper McNeil.
"He's a pure goal scorer. He can score from the left and right foot or a header, as he did today.
"He's a pleasure to work with. He's a raw talent but he will keep getting better," Great-holder said of the former YoungHeart Manawatu player.
The hosts employed the long balls to the inside or edge of the 18m box with monotonous regularity but commendably Robertson and his other three defenders - Harley Rodeka, Danny Wilson and Aaron Jones - kept rendering them redundant.
"Bill was super and I'm very proud of all four of them," the coach said, adding they showed a lot of resilience to defend with aplomb.
He gave his midfielders an "okay".
Greatholder lauded the opposition, saying they were always going to be tough customers after having beaten Canterbury United but losing controversially to Auckland City the previous weekend.
"They will be taking points off all sides," he said of the Peter Smith-coached WaiBOP.
Referee Nick Waldron flashed five yellow cards. Sean Lovemore and Biss were the Bay's collectors.
Greatholder led Bay United, who are undefeated after three rounds with the opening round against newcomers Wanderers Soccer Club postponed to Waitangi Day, to their only playoffs in the eight-year history of the national summer league.
The Bay host Team Wellington on Saturday at 5pm at Bluewater Stadium, Park Island.