Ben Askren told Jake Paul he needed to "take a s***" during their final face-off.
The former MMA star will take on the YouTube sensation, who is fighting for a third time as a professional.
Askren meanwhile is making his boxing debut on Saturday night, but has been accused of treating the bout as a "joke".
The pair both weighed in at 191lb, but Askren appeared out of shape.
And Paul has opened up on their exchange during their final face-off.
He said: "I see a guy who's underestimating me, I see a guy who is taking this as a joke and I see a guy who said, 'I have to take a s***' during the face-off.
"This is the last 24 hours we will all have to hear Ben Askren. This one means a lot for me, this one is for Shadow (Paul's bodyguard).
"I don't believe he makes it out of two rounds; look at the guy, he has a beer belly so he clearly didn't take training camp seriously.
"We all did the talking and the entertainment s*** but now it's time to let the fists fly."
Askren has claimed he will stop his opponent in the seventh round ahead of his $500,000 pay day.
It comes after the 36-year-old recently stated that he wasn't overly concerned with winning.
"I honestly think most fans are more invested in the result of this belt than I am," he said.
"I mean for me, I think actually the biggest negative comes from winning, because if I beat Jake Paul’s ass, I’m going to be world famous.
"And I ain’t really trying to be world famous. Like I said, I’m trying to coach wrestling and podcast and that that’s really it. So the result of that bout on Saturday night, obviously I I’d like to win, but I don’t really think it changes my life a whole lot either way."
