Trainer Kevin Barry says he still kicks himself about the way he approached that fight with Parker. It is, he says, a pivotal point in the development of the "second phase" of Parker's career, which starts tomorrow (Sunday) in Providence, Rhode Island.
Parker will meet fellow Samoan Alex Leapai in a heavyweight clash, though Parker weighed in at a trim 109kg, a full 6kg lighter than his opponent. On this occasion, they believe lean will equal mean.
Part of Barry's approach with Parker has been to have him better prepared for boxing's darker arts.
"People look at the Dillian Whyte fight where we got outmuscled," Barry said. "We got outmuscled in a totally illegal fashion but the referee allowed Whyte to get away with it.
"People look at that and say that is the way to beat Joseph Parker. I'm disappointed in myself that maybe I hadn't given Joe enough [preparation] for the down and dirty part of the professional game. If there was ever a fight where we needed a down and dirty reaction, it was the Dillian Whyte fight because he fouled Joe from beginning to end.
"If the fight was here in America, Whyte would have been disqualified inside six rounds."
All week, conversations with members of Parker's team have been peppered by references to that fight, whether it be the gamble they took in agreeing to the fight on short turnaround, the acknowledgment that he likely needed just a minute more to get the KO he needed to win, or the fact he fought through a heavily concussed state to stay in the game.
If the latter point sounds a little macabre, it's also the thing that reaffirmed to Barry that he has a special fighter in his care.
"He caught the headbutt to the cerebellum that most people played down, saying 'these things happen in boxing.' No they don't, no they friggin' don't.
"Joe was concussed from the second round. Most guys would have never, ever got up… it was a phenomenally damaging blow but it showed the character of the man. The fact that even in a concussed state, and a state where he had lost total control of distance – he was thinking he was safe and he was getting hit by jabs – yet he still grafted and grunted away and we came within a hair's whisker of pulling off a sensational last-round knockout."
Barry said they will never go into a fight again unprepared for the worst. That could even apply to this fight, as the expectation is that Leapai cannot live with Parker on skills alone.
"He's a physical guy. He's strong. He's going to try to use that. He's going to try to use that physical strength to impose himself on Joe. It's not rocket science. It's the only way he can possibly put himself in position to be successful.
"He's not going to try to out-box Joe; he's not going to out-skill him. He needs to outmuscle Joe, that's his only show."
Parker spent the day before his fight eating pasta and chicken, taking part in an outdoor weigh-in in the roasting dish disguised as downtown Providence and relaxing. In the morning he completed a surprising robust training session that included three rounds of pad work and a further round of shadow boxing.
"Joe's quite unusual for the simple fact he's one of the few fighters that I've worked with who likes to do a shakeout on weigh-in day. Most guys, unless they're trying to make weight, do nothing.
"The one time I can remember us not doing it, was the Dillian Whyte fight."
Lesson learned.
