REUTERS/Rebecca Cook
Ben Carson.
According to The New York Times/CBS News survey released Tuesday morning, Carson garnered 26% support among GOP primary voters.
Trump followed with 22% - within the margin of error.
While volatility is expected in primary polls, this latest development is notable because of how completely Trump has dominated such surveys since the summer, when he rocketed to the top.
But Carson gained the lead in two Iowa polls last week, while Trump remained ahead in the national ones.
Trump responded to the Iowa results by aggressively taunting Carson in his stump speeches and media interviews. Among other things, Trump called Carson "super-low energy," said he was controlled by his super PAC, blasted him as "extremely weak" on illegal immigration, and even appeared to question his Seventh-day Adventist faith.
"He'll hit back, everybody hits back," Trump predicted Monday of Carson, who has yet to return fire. "In life, everybody hits back."
According to The Times, no other Republican contender even had double-digit support in the poll. Sen. Marco Rubio (R-Florida) had 8% followed by former Florida Gov. Jeb Bush (R) and former Hewlett-Packard CEO Carly Fiorina, who tied at 7% apiece