Tony Schwartz, the man who ghostwrote Donald Trump’s best-selling book “The Art of the Deal,” has tips for Hillary Clinton on how to squash The Donald during Monday’s presidential debate: “Torture him with his own words.”

“You break down his persona by showing how he’s really not nearly as intelligent as he says he is and would like to be,” Schwartz told the New York Times’ podcast “The Run-Up” on Friday. “He can’t avoid repeating himself. He can’t stay focused on a subject for very long.”

“I’d be very calm, direct, and unflappable but relentless — and I mean relentless — over 90 minutes in calling out every time a line came out of his mouth,” Schwartz went on to say. “I’d call out his repetitions calmly, unflappably but confidently.”

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Schwartz — who has become an outspoken Trump critic since the real estate mogul entered politics last year — offered his help to the Clinton campaign after admitting that he was guilt-ridden for his part in creating the Trump brand in the late ’80s.

“He is a very effective provocateur,” he warned, adding that Clinton would be wise to try and rile him up. “America would probably want to see that the person they choose to vote for for president is someone who seems presidential, who seems calm under pressure so I think any evidence of that can only serve the person who demonstrates it. “

How does one get Trump all riled up?

“I don’t expect him to blow up in a temper tantrum,” he said. “But you get under Donald Trump’s skin by exposing that there is no ‘there’ there beyond the bluster,” adding, there is no “wizard behind the curtain.”

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According to Schwartz, the former secretary of state should hit him on issues like “John McCain, the Khans, about knowing more than the generals about ISIS, about the birther claims.”

“You keep coming back to it because it’s his words,” Schwartz said. “And there’s no ultimate way of his getting out of it, except to deny it. And what is denying it? It means doubling down and that’s what he’ll always will do if you push him hard on the lies that he tells.”

“And that’s where he’ll be in enormous trouble the next day,” he added.

You can listen to the entire interview here.