The usually mild-mannered Ben Carson -- who's been accused by rival Donald Trump of being too "low energy" -- is flashing a feistier side as he defends himself against questions about his personal story, leaving pundits and rivals wondering whether he will "change the narrative" at Tuesday night's fourth Republican presidential debate. 

Tensions between the top GOP candidate and the media reached a flashpoint Friday night during a press conference in which he had heated exchanges with reporters. The retired neurosurgeon also has sparred with the media in other interviews in recent days. 

"Don't lie," Carson said in accusing a "biased" media of orchestrating a political "witch hunt." 

He suggested Sunday he's not backing down. "People ... are saying, 'Don't let them do this to you,'" Carson told ABC's "This Week." 

Carson will be center stage along with Trump on Tuesday night for the Fox Business Network/Wall Street Journal debate in Milwaukee. 

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Republican strategist David Payne argues that Carson will have a great opportunity on Tuesday to "change the narrative after a week of bad headlines," though he needs to be prepared. 

"If he goes into the debate talking about ObamaCare and other health care issues, he can own the stage," Payne, a partner at the Vox Global firm, told FoxNews.com on Monday. "He can show a lot of energy because he knows this topic." 

Still, Carson is not alone in having to challenge the media as well as rivals who are lobbing attacks based on critical stories. Florida GOP Sen. Marco Rubio arrives in Milwaukee for the debate in a similar situation, facing increasing scrutiny, specifically over personal finances, as he climbs in the polls. 

Though the debate is expected to focus on jobs, taxes and other economic issues, Trump shows no signs of changing his admitted strategy of going after his closest competition, as he and Carson trade the lead. 

On Sunday, Trump coyly needled Carson -- whom he has called "super low-energy" -- about news stories challenging autobiographical accounts of Carson's youth. 

"I hope it all works out for him," he said on ABC before making almost identical statements on CBS, CNN and NBC. In reference to reports about Carson's troubled youth, he said: "It's a strange situation though when you talk about hitting your mother in the head with a hammer and ... stabbing somebody." 

Brian Morgenstern, vice president of the Manhattan Republican Party, thinks the pressure is on Trump, who touts his economic smarts but on Tuesday will face three senators with "big, smart staffs." 

"They have some chops here and they can keep up with him," he told FoxNews.com. 

The media scrutiny on Carson, a retired neurosurgeon and first-time candidate, started after back-to-back polls in late October showed him taking over Trump in Iowa. And it intensified as other polls showed him surpassing Trump in the national race, though the latest Fox News poll showed Trump slightly ahead. 

Late last week, Politico published a story challenging the claim that Carson received a scholarship offer from the U.S. Military Academy at West Point -- Carson later said he was told he'd have an "easy" time if he applied, but acknowledged there was no scholarship offer. Those accepted into the academy get free tuition. 

CNN also reported finding no support for Carson's oft-repeated claim that he as a teen tried to stab a close friend. And The Wall Street Journal had a story stating no evidence could be found to support Carson's claim that a classroom incident while at Yale was reported in the school newspaper. 

"We found it," Carson countered on Sunday. 

Morgenstern also noted the dynamics will be different Tuesday, compared with the first three, main-stage GOP debates, because it will not include New Jersey Gov. Chris Christie and former Arkansas Gov. Mike Huckabee. The two will be in the earlier undercard debate. 

"Carson has not been much of a factor in the debates, and I think everyone expects that to change," Joe Desilets, Republican strategist and managing partner at the firm 21st & Main, said Monday. "I expect Carson to stay calm, maybe a bit more emphatic in his delivery, but choose his words carefully as he has done in past debates. If he takes the bait from any of the candidates and his demeanor breaks and he doesn't handle it well, his time at the top of the polls may be coming to an end."

Rubio has faced questions about his spending and finances since he ran for the Senate in 2010, only to face more scrutiny amid his roughly 6-point rise in polls since late September. 

"Marco Rubio can't even handle his own credit card how is he going to be able to handle the U.S. finances," Trump tweeted Friday. 

Rubio, whom most polls show now in third place, the following day released more charge card statements, in an apparent attempt to curtail the continued questions and criticism. 

The statements were for an American Express card issued by the Republican Party of Florida when Rubio was a state lawmaker and covered the period January 2005 to October 2006. 

They showed Rubio spent almost $65,000 with the card, including more than $7,200 for eight personal expenditures. 

Rubio's campaign said he paid American Express directly for the personal charges. And the state GOP party issued a statement saying it "did not pay for any of Marco's personal expenses" and that "taxpayer funds were not used for any political or personal charges." 

The Associated Press contributed to this report.