Barry and Parker head back to their home in Las Vegas today, a week after the 23-year-old of Samoan heritage destroyed German Yakup Saglam in Palmerston North.
Parker's hand speed was stunning.
It was his 14th consecutive victory as a pro.
Even boxing sceptics are holding their tongues when it comes to Parker.
When we meet at an Auckland cafe, he proves very easy to like.
Brought up in Mangere East, boxing loomed large. His father, Dempsey, was named after the American boxing legend Jack.
Boxing-crazy Dempsey Parker gave gloves and pads to Joseph when he was 4. Game on.
"I grew up watching boxing videos and he started taking me to different gyms," says Parker.
Dempsey, a steel worker, and his wife Salavao, a social welfare worker, got into hock to fund their son's amateur career, which took him around the world.
When Lonergan - a long-time friend of Barry's - and David Higgins from Duco took over Parker's management, Barry was their man.
Lonergan said Barry's understanding of Pacific Island culture and the role of family was vital.
Barry said: "I am now Joseph's teacher, friend, mentor, trainer, manager, life coach. I am sharing with Joseph a lifetime of experience I have in boxing."
It could have been a tough decision for Parker, since Barry's relationship as coach with David Tua ended in a draining legal battle.
"The Samoan community had sympathy for David Tua and a lot thought it was a strange decision," says Parker.
"But ... I have so much faith and trust in Kevin, the bonds we have. His wife is like a mum to me. His kids treat me like a brother."
Technically, Parker now fights like a big man, looking to "control the zone", his strong chin no longer an inviting target. This year, Parker paid off his parents' mortgage.
"It was the best feeling in the world as a son," he says.
"I can already see the difference in them, not having the financial stress.
"They are at my fights and I fight for them."
