“All I can say is this: I watched him with Paul Ryan, and he destroyed Paul Ryan. Paul Ryan with the water, he was chugging water left and right … and he beat Paul Ryan. So, I’m not underestimating him. I’m not underestimating him. It is what it is,” he said.

Trump’s remarks came as CNN political commentator Van Jones, who worked for the administration of former President Obama, warned that if Biden makes a mistake at the debate it could be the end of his presidency.

“This is the entire election, as far as I’m concerned. The entire world will be watching,” he said in an interview with CNN’s Jim Acosta. “If you are a carbon-based life form, you’re going to be watching. If you’ve got a functioning brain stem, you’re going to be watching.”

“Because if Biden goes out there and messes up, it’s game over. If he walks out there, and a week later he’s lower in the polls, it’s panic in the party,” he said. “But if he goes in there and he can handle himself against Donald Trump — a runaway train, a locomotive, a raging bull — then this guy deserves another shot to be president, because that is tough.”

Jones characterized debating against the former president as a tough task that no normal person could undertake.

“You couldn’t do it. I couldn’t do it,” he said. “If you can stand toe-to-toe with a runaway train like Donald Trump for an hour and a half, you are fit to be president, period, point-blank.”

“This is the whole presidency in a bottle in a week,” he said.

On Saturday, Biden retreated with close family members to discuss his reelection path forward after his bad performance.

NBC News reported that Biden huddled with his family at the Camp David presidential retreat in Maryland after a debate “that left many fellow Democrats worried about his ability to beat” Trump in the fall, according to five sources.

The outlet said that the trip was planned before the debate. The president and first lady Jill Biden joined their children and grandchildren late Saturday.

“So far, the party’s top leaders have offered public support for Biden, including in tweets posted by former presidents Barack Obama and Bill Clinton. Senior congressional Democrats, including Reps. Hakeem Jeffries of New York, Jim Clyburn of South Carolina and Nancy Pelosi of California, have privately expressed concerns about his viability, said two sources apprised of those discussions, even as they all publicly back the president,” NBC reported.

“One Democratic House member who believes Biden should drop out of the race — but has yet to call for that publicly — told NBC News that three colleagues expressed the same sentiment to him during votes on the House floor Friday,” the outlet added, noting further that House Democratic leaders are publicly supporting Biden but privately expressing doubts about his viability against Trump.

Late Sunday, however, reports noted that Biden’s family convinced him to remain in the race.