Sonny Bill Williams is a better athlete than Michael Jordan, according to the man he next faces in the boxing ring.
And that scares experienced American Chauncy Welliver.
"This guy is an all-round athlete - he can run, he can jump, he can do a little bit of everything," Welliver said on Wednesday's ahead of Saturday's heavyweight main event in Sydney.
"You're not going to find a better athlete, not in America, not in Australia.
"This guy is a better athlete than Michael Jordan.
"You look at me, I'm not the most athletic guy in the world, but the one thing I'm going to bring on Saturday night is heart and balls.
"I'm going to bring it, I'm going to make a fight of it, and we're going to see if Sonny Bill can actually fight."
The former New Zealand heavyweight champion has more than 10 times the number of fights under his belt, and labelled his Kiwi opponent "just like a kid in my sport".
But Welliver said that seeing Williams' last fight - a controversial 10-round victory over South African Francois Botha in February 2013 - had made him nervous.
"He looked amazing against a guy that was beating Mike Tyson, beating Evander Holyfield, and he dominated," the 31-year-old said.
"Obviously he got a little tired in the later rounds and I'm hoping that's the case Saturday night, but he dominated a good veteran.
"I hope I can show him some new things on Saturday night."
Williams admitted he was a "little bit too cocky" going into his fight with Botha, having underestimated how much preparation he needed to face the seasoned professional.
"I didn't do myself justice and respect the sport, hence the reason the last couple of rounds I was out on my feet," he said.
"But I'm really happy with the way the prep's gone this time, seven-eight weeks of tough, hard training, and I'm just really keen to get out there."
Saturday night's clash will be Williams' seventh professional bout before returns to Super Rugby with the Chiefs after two years playing in the NRL.
Welliver has had 70 fights with 55 wins and five draws.
"You've got to respect that - and I definitely do," Williams said.