(NewsNation) — Bill O’Reilly told “On Balance with Leland Vittert” on Tuesday that if former President Donald Trump doesn’t “win” the Sept. 10 debate, he will likely lose the election to Vice President Kamala Harris.

So, how does he win? O’Reilly believes the GOP nominee needs to stay under control and get Harris off script to clinch the debate and, ultimately, the 2024 election.

“If you’re Trump, you have to define her. You have to define her by either asking a question or making a statement,” O’Reilly said. “She doesn’t know why inflation rocketed. She doesn’t know how to solve the Middle East.“

NewsNation’s Leland Vittert questioned that logic, telling O’Reilly, “She’s going to have a memorized answer for all of those. She’s going to debate camp for five days.”

But her prepped answers, according to O’Reilly, “don’t make sense.”

O’Reilly also believes Trump could sway undecided voters if he is able to tout his presidency over her record.

“I think there’s about 10% of persuadable, apathetic voters, people who don’t pay attention to last minute. It’s like shopping on Christmas Eve, OK?” he said, adding that those voters can be moved if he demonstrates that Harris has to own the Biden administration’s failures.

“You’ve got to tie in Kamala Harris with [Joe] Biden, and the only person who can do it is Trump. The president isn’t going to do it. The pundits can’t do it, but Trump could do it if he starts to make statements that are simple and clear in the debate,” O’Reilly said.