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President Trump's attorney Rudy Giuliani previewed Tuesday night's first presidential debate against Joe Biden as he is prepping the commander-in-chief.

"The president will do very well tonight," Guiliani told "Fox & Friends," saying he is better prepared now against the Democratic presidential nominee than he was four years ago against then-candidate Hillary Clinton.

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"Biden is a nasty enough guy that you don't have to worry about, you know, being too careful with him," Giuliani said. "He said terrible things about the president, so the president has every right to take his head off if he wants."

Former Vice President Joe Biden and President Trump will square off in their first presidential debate, Tuesday, Sept. 29, 2020. (AP Photo/File)

Former Vice President Joe Biden and President Trump will square off in their first presidential debate, Tuesday, Sept. 29, 2020. (AP Photo/File)

Giuliani and former New Jersey Gov. Chris Christie have reportedly been helping Trump with debate prep as he squares off against Biden in Cleveland with Fox News' Chris Wallace as debate moderator for the first of three general election debates.

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"I think this is a great opportunity for the president to really just be himself. He doesn't have to hold back very much. He doesn't have to hold back at all really," Giuliani said. "Joe is a really, really big phony."

The former New York City mayor argued that Trump is better prepared now because he is answering questions from the press every day: "He is very well-prepared."

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The host of "Rudy Giuliani's Common Sense" podcast said the president has a great record despite being interrupted by the coronavirus pandemic and accused Democratic governors of playing politics by keeping their states deliberately shut down.

"You don't want to change to a left-wing philosophy now," he said about Biden. "This is the worst time to raise taxes. I mean, people have no money. He'll crash the economy ... if he does half of what is he talking about, he'll crash the economy."

Giuliani said the New York Times' Sunday report on Trump's taxes -- which the president called "fake news" -- is "garbage," noting that Trump didn't break any laws and questioning Hunter Biden's connections to Russia and China after the Burisma report.

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"How come you are not examining the 3.5 million that his son got from one of the closest people to Putin? How come you're not examining the three high-level members of the Chinese Communist Party who is business partners one of whom recruited intelligence sources for the Chinese Communist government?" he asked.

And on Trump's Supreme Court nominee Judge Amy Coney Barrett, another debate topic, Giuliani warned: "Joe better stay away from her religion."