Sen. Ted Cruz, backed by the tea party and conservative Republicans, has replaced Ben Carson as Donald Trump's closest competitor in the first caucus state of Iowa, according to a new Quinnipiac University poll released Tuesday that shows Cruz in a virtual tie with Trump when accounting for the margin of error.

The billionaire real estate mogul still came out on top with 25 percent support of likely Republican caucus-goers, though Cruz, a freshman Texas senator, followed with 23 percent. That's more than double where Cruz stood in the same poll in October and well within the 4 percentage point margin of error, reports CNN.

Retired neurosurgeon Carson, who edged out Trump for the lead in last month's poll, now sits in third with 18 percent, down 10 points. Florida Sen. Marco Rubio took fourth with 13 percent, holding steady from last month's poll. Kentucky Sen. Rand Paul garnered 5 percent, former Florida Gov. Jeb Bush came in at 4 percent, and businesswoman Carly Fiorina followed with 3 percent. No other candidate earned more than 2 percent.

"Last month, we said it was Dr. Ben Carson's turn in the spotlight. Today, the spotlight turns to Sen. Ted Cruz of Texas. The Iowa Republican Caucus has become a two-tiered contest: Businessman Donald Trump and neurosurgeon Ben Carson lead on the outsider track, and Sens. Ted Cruz and Marco Rubio lead among party insiders," said Peter A. Brown, the assistant director of the Quinnipiac University Poll, reports The Hill. "The other candidates will need miraculous comebacks to crack the top tier with slightly more than two months before the voting begins."

Among Republicans identifying with the tea party, an astounding 42 percent supported Cruz, nearly twice that of Trump, who got 23 percent support from that group.

Cruz also led Trump among those who described themselves as very conservative, 38 percent to 21 percent, but Trump was the favorite among respondents who described themselves as only somewhat conservative, as well as those who described themselves as moderate or liberal.

White, born-again Christians also preferred Cruz over Trump and Carson, with the Texas senator earning 27 percent to Carson's 24 percent and Trump's 20 percent, notes Politico.

While Carson's poll numbers dropped significantly, he still has the best favorability ratings - 79 percent positive to 15 percent negative.

Cruz followed, with 73 percent viewing him favorably compared to 15 percent unfavorably, and Rubio was next, 70 percent to 18 percent. Fifty-nine percent viewed Trump favorably, compared to 34 percent unfavorably. Bush's favorability ratings have taken a big hit, with only 39 percent viewing him favorably compared to 53 percent holding unfavorable views.

Most likely GOP voters, 24 percent, said the economy and jobs are the most important issues in deciding who to support, followed by terrorism and foreign policy at 15 percent, the deficit at 11 percent and immigration at 10 percent.

Trump was judged as the best candidate to handle the economy, with 24 percent, far ahead of Cruz's 11 percent. Most also think Trump can handle terrorism the best, 30 percent, compared to 20 percent for Cruz. Cruz won the highest marks on foreign policy, with 24 percent.

The survey was conducted among 600 likely Republican caucus-goers from Nov. 16-22 and has a margin of error of plus or minus 4 percentage points.