Washington (CNN) — Ben Carson has knocked Donald Trump from his perch atop the field in Iowa, according to the latest Quinnipiac University poll of Iowa Republicans.

Carson has opened up an 8 percentage point lead over Trump with the help of women and white evangelicals, who overwhelmingly favor the soft-spoken former neurosurgeon over the outspoken billionaire. About 28% of likely caucus-goers said they support Carson, 20% back Trump, 13% support Florida Sen. Marco Rubio and 10% are for Texas Sen. Ted Cruz.

The survey is the first major poll to find Trump trailing by a significant margin nationally or in the four early states since a CNN national poll taken June 26-28, which showed Trump behind Florida Gov. Jeb Bush 12% to 19%.

The latest Quinnipiac poll shows Carson winning big with two key groups: women back Carson over Trump 33%-13% and white evangelicals support him 36% to Trump’s 17%.

Carson is the only candidate in the GOP field to consistently poll in the top tier near Trump, running a strong second in most national polling in the past month and easily outpacing other competitors. Former tech CEO Carly Fiorina’s post-debate bump recently evaporated, although Rubio has been steadily rising in the polls.

Read the article “Ben Carson Knocks Donald Trump from Top Spot in Iowa” on cnn.com.