Republican presidential candidate Donald Trump just took a big hit in the crucial first-in-the-nation caucus state of Iowa, slipping to second place behind retired neurosurgeon Ben Carson in a Quinnipiac University poll released Thursday.

Carson, riding a wave of support from women and evangelical voters, now leads in Iowa with 28 percent among likely Republican caucus-goers, compared to Trump's 20 percent. A Sept. 11 poll by Quinnipiac showed Trump at 27 percent and Carson at 21 percent, noted the New York Times.

While the two outsider candidates received roughly the same amount of support from men, Carson earned 33 percent from women, while only 13 percent of women supported Trump. Carson also led Trump among Iowa's large white, evangelical Christian community, 36 percent to 17 percent.

Carson's success was bolstered by his almost unheard of favorability ratings among likely Republican caucus-goers, 84 percent favorable to 10 percent unfavorable. That's compared to Trump's 53 percent to 43 percent favorability rating. A huge majority, 87 percent, also feel that Carson cares about their needs and problems, the highest mark among any Republican candidate.

"It's Ben Carson's turn in the spotlight," said Peter A. Brown, the assistant director of the Quinnipiac University Poll. "As they've been pondering for six months, many in the political world still are trying to understand Carson's appeal and how someone who seems to be operating outside the traditional news media/political environment is doing so well among the most conservative G.O.P. voters."

Trump, however, was given the highest mark for strong leadership qualities, 80 percent, compared to Carson's 76 percent.

Most also believe the billionaire real estate mogul is best equipped to handle a number of different issues. On the economy, Trump tops Carson 41 percent to 12 percent. On taxes, Trump took 32 percent compared to Carson's 13 percent. And on immigration, Trump came out on top with 37 percent while Carson got 9 percent.

Behind Carson and Trump was Florida Sen. Marco Rubio with 13 percent, who also climbed 8 points in the last month. Texas Sen. Ted Cruz came in at 10 percent, Kentucky Sen. Rand Paul at 6 percent and former Florida Gov. Jeb Bush and businesswoman Carly Fiorina tied with 5 percent. The rest of the candidates have 3 percent or less.

The poll was conducted Oct. 14-20 among 574 likely Iowa Republican caucus participants and has a margin of sampling error of plus or minus 4.1 percentage points.