Donald Trump, former president of the United States, challenged incumbent Joe Biden to a boxing match on Thursday after the country's 45th leader was knocked out at the ballot box in last year's national elections.

Trump said his "easiest fight" would be against Biden when asked who we would fight during a promotional event for this weekend's Evander Holyfield vs. Vitor Belfort fight, for which the former president will be providing ringside commentary.

"I think he'd go down very, very quickly; very, very quickly," Trump said by telephone as he called into the event. "He once said, 'Oh, I'd like to take him behind the barn.' He'd be in big trouble if he ever did. I think Biden would go down within the first few seconds."

Trump was referring to comments Biden made in March 2018. Biden was reacting to Trump's claims that as a celebrity he could sexually assault any woman he wanted, including grabbing their genitalia. The comments were made behind closed doors, but were leaked to the press early in Trump's presidency.

"If we were in high school I'd take him behind the gym and beat the hell out of him," said Biden.

Trump has refused to accept his electoral loss and has claimed without providing a shred of evidence that he was defeated due to widespread voter fraud. That claim was rejected by Trump's former attorney general after a Justice Department probe failed to establish any evidence to support the claim.