After showing his professionalism and poise in a unanimous points victory over Carlos Takam in May, Parker illustrated his punching power to send the Australian to the canvas and thrill the home fans.
"Most fighters have knockout power and it's just a case of landing it," a satisfied Parker said post-fight. "It landed flush, and when it lands flush any fighter can go down."
That knockout power was questioned in some quarters after Parker out-duelling the sturdy Takam in Manukau, a fight that also revealed a few defensive flaws.
Parker barely had enough time in the ring tonight to showcase any amendments he had since made, applying enough pressure to render defence largely unnecessary, although Haumono did pursue him from the opening bell.
The Kiwi kept out of trouble with good head movement and footwork, ending the contest before there was any possibility of repeating the mid-fight lapse that saw his hands drop against Takam.
Parker did start cautiously as he sought to stay clear of Haumono's dangerous right while landing his own shots, failing to make much of a connection in the opening two rounds.
The fight became Parker's in the third, though, when, after some mid-round advice from his corner, he both better established his jab and made an emphasis on working Haumono's body.
The Australian looked like he was wearing down from the blows and that soon proved the case, when Parker unlocked his opponent's defence and sent him sprawling backwards.
"I started throwing the jab more in [the fourth] round and, when the jab started landing, it was hitting him in the face," Parker said. "That set up the right uppercut, which he didn't see coming."
Haumono was still struggling to work out what had hit him as referee Bruce McTavish reached the end of his count, eventually staggering to his feet but not before the fight was over.
The veteran's corner disputed that decision and soon lodged an official protest, arguing their fighter had beaten the count, but Parker was already eyeing his next move.
He is set to fight again in October, continuing a relentless schedule that has seen him steadily ascend the heavyweight ranks. No opponent has yet been confirmed for that fight - an announcement will be made on Tuesday - but it's tough to imagine Parker's shot at the IBF crown being subject to too much risk.
Whether he is yet ready to rock the unbeaten Joshua remains to be seen. But Parker's elevation to the world stage appears imminent.
• Kris Shannon is in Christchurch with assistance from Duco
