Presidential candidate Donald Trump on Wednesday will for the first time enter a GOP primary debate without the title of undisputed frontrunner and likely looking to tangle with challenger Ben Carson who’s taking over in recent polls.

A poll released Tuesday has Carson leading nationally and follows two others that show the soft-spoken retired neurosurgeon leading in Iowa, which already had Trump on the attack.

“I'm surprised at Ben Carson, but I go after Ben Carson,” Trump told MSNBC before the CBS/New York Times poll showed Carson ahead 26-to-22 percent. “That's my whole life. If somebody is an opponent, I want to win.Ben Carson is now doing well.”

To be sure, Carson has steadily climbed in polls -- from 6 percent in early August to 22 percent this week, according to an averaging of polls by RealClearPolitics.com.

But whether he will now break from his low-key, voter-friendly demeanor and fight back remains to be seen.

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The two will potentially tangle next at Wednesday night's third GOP debate hosted by CNBC and held in Boulder, Colo.

Carson recently declared on “Fox News Sunday” that he wouldn’t “get into the mud pit” with Trump, echoing earlier comments.

“I'm certainly not going to get into that, no matter what anybody says,” he added.

However, other Republican candidates have made similar declarations, then succumbed with mixed results.

Trump drew top-tier GOP candidate Jeb Bush into an extended exchange, which he ignited last month during the second GOP primary, about the administration of his brother, President George W. Bush.

The former Florida governor had thus far vowed to run on his own record and ignore Trump’s constant, sometimes personal attacks.

“He’s not a serious candidate,” Bush said repeatedly.

However, he then decided to fight back, despite knowing the perils of rehashing his brother’s political legacy, including the events before and after the 9/11 terror attacks. And his decision to engage and stray from touting his own agenda was criticized as a misstep.

Trump, who still leads in most national polls, has been needling Carson along his steady climb, which since late August has turned the race for the party nomination into a two-man contest, with the overwhelming majority of polls showing the other 12 GOP candidates trailing by double digits.

After repeatedly calling Carson “super low energy,” Trump this past weekend mentioned that Carson is a Seventh Day Adventist, a religion that some voters, particularly those in Iowa, considered non-Christian.

"I'm Presbyterian," Trump said during a campaign stop in Florida. "That's down the middle of the road. I mean, Seventh-day Adventist, I don't know about."

Carson said Sunday that he hoped Trump would “have the same grace” and apologize, just like he did when questioning Trump’s faith in September. Trump has declined to apologize, saying he did nothing wrong.

Last week, a Des Moines Register/Bloomberg Politics poll showed Trump now trailing Carson by 9 percentage points in Iowa. And a Quinnipiac University showed him trailing Carson by 8 percentage points among Iowa Republican voters.

If Trump follows his attacks line Wednesday, he will continue to go after Carson for his limited business experience and positions on abortion, immigration and Medicare.

Carson opposes abortion under any circumstance, including rape and incest. This past weekend, he compared women seeking abortions to slave holders but told NBC that he’s open to “a reasonable explanation for why they would like to kill a baby.”

Trump has called Carson “very weak” on illegal immigration. And on Tuesday, he again touted his international influence and business acumen.

“I'm doing many deals right now all over the world. I deal with prime ministers and heads of country,” he said. “I will make the best trade deals. I will be strongest and best on the military.”

Carson has argued that he made plenty of business decisions as director of pediatric neurosurgery at Johns Hopkins Hospital.

Still, the Medicare issue might bring the biggest fireworks Wednesday.

Carson said on Sunday that he no long wants to dismantle Medicare and now prefers so-called health savings accounts as an alternative to the government-subsidies medical insurance for retirees.

However, Trump on Tuesday argued otherwise.

“Ben wants to knock out Medicare,” he said. “I heard that over the weekend. … I don't think you'll get away with that one. It's actually a program that's worked. It's a program that some people love, actually.”