President Donald Trump hit back at JP Morgan Chase CEO Jamie Dimon on Thursday, belittling the banking chief as a "nervous mess" after Dimon had boasted he was smarter than the president and could beat him if he chose to run.

"The problem with banker Jamie Dimon running for President is that he doesn't have the aptitude or 'smarts' & is a poor public speaker & nervous mess," Trump wrote.

The president added, "otherwise he is wonderful. I've made a lot of bankers, and others, look much smarter than they are with my great economic policy!"

The problem with banker Jamie Dimon running for President is that he doesn’t have the aptitude or “smarts” & is a poor public speaker & nervous mess - otherwise he is wonderful. I’ve made a lot of bankers, and others, look much smarter than they are with my great economic policy! — Donald J. Trump (@realDonaldTrump) September 13, 2018

The tart tweet came less than 24 hours after Dimon, who has been a major fundraiser for Democrats, said he was "smarter" than Trump and could defeat him.

"I think I could beat Trump," Dimon said at an event at his company's New York headquarters. "Because I'm as tough as he is, I'm smarter than he is."

"He could punch me all he wants, it wouldn't work with me. I'd fight right back," Dimon said.

"And by the way this wealthy New Yorker actually earned his money," Dimon said. "It wasn't a gift from Daddy."

Moments after he made the remarks Wednesday, Dimon, 62, issued a statement, taking them back.

"I should not have said it. I'm not running for President,” he said. "Proves I wouldn't make a good politician. I get frustrated because I want all sides to come together to help solve big problems."