Kiwi heavyweight Junior Fa has been in the ring with Deontay Wilder, perhaps the most feared puncher in boxing, and is certain the American will stop Tyson Fury in their world title fight in Los Angeles this weekend.
Fa, who has just returned from four weeks of sparring with Wilder in Alabama, knows first-hand what Englishman Fury is up against.
"In terms of power he hits hard," Fa said of Wilder.
"I didn't hang around to be hit ... I think I did the best Tyson Fury impersonation that I could and I hope that goes well for Deontay on Sunday.
"It's going to be a hard fight and pretty awkward. Both fighters are pretty tall, both fighters like to fight off the back foot, so you are going to need an instigator and I'm not sure who will come forward first.
"But I'm picking Wilder to end the fight. I don't know when but I feel like he will find a way and definitely will take him [Fury] out."
Wilder, the WBC world champion, has an added advantage in that he is fighting on home soil and has been a consistently busy – and devastating – professional. He has a perfect 40-win, no-loss record, with 39 knockouts. Fury is also undefeated but has 19 knockouts in 27 victories and has fought only twice since upsetting Wladimir Klitschko in late 2015.
Fury's well-publicised issues with mental health and substance abuse meant he had to relinquish his belts and there is a suspicion that the time out of the ring has taken an edge off him.
But either way the 30-year-old is set for a big pay-day and big fights back in his homeland, the centre of the heavyweight game with Anthony Joshua and Dillian Whyte looming.
And for Fa the stakes are high too ahead of his December 15 fight in Christchurch against Argentine Rogelio Omar Rossi on the undercard to Joseph Parker's fight against Alexander Flores.
Fa, 29, said he is over his health issues which included a low red cell blood count and elbow injury, and is ready to add to his perfect 15-0 professional record.
Sparring three or four rounds a day against Wilder should have helped Fa's mental and physical fitness.
"It has done great things for my confidence, knowing that if I could hang in there with him I'm pretty sure that I could be fine with the other top pros in the division," Fa said.
"But the best thing I got out of camp wasn't physical, it was to see how he thinks, how he deals with the pressure with hours of TV interviews and then coming to training.
"Just to be in that environment with him and see how he deals with things mentally. It was a great thing to see first hand and I got a lot of things out of it."
A good win for Fa, the WBO oriental heavyweight champion, could improve his ranking with the organisation – he is currently ranked No10 by the WBO – and there are bigger fights ahead, including possibly Joshua and fellow Kiwi Parker.
Parker's promoter David Higgins said the fight could definitely happen but that Fa still had work to do.
"Like Tua-Cameron, everyone likes the local contest," Higgins said.
"I think if Junior can string together some more solid wins then it just heats up over time. It really is in Junior's hands to show if he can develop and become more skilful and formidable. As that happens, the public and the media are going to call for that test to happen to see who is the better of the two.
"So yeah, I can see that happening, maybe a couple of years down the track."