Donald Trump's new top rival is exploding in New Hampshire

Retired neurosurgeon Ben Carson is making huge gains in the Republican presidential primary's early states - first in Iowa, and now in New Hampshire.

A new Monmouth University poll of likely New Hampshire Republican primary voters released Monday again shows real-estate mogul Donald Trump leading the pack, with 28% of the vote among likely Republican voters.

But it's Carson who has made the biggest strides over the past two months. According to the poll, 17% of likely Republican primary voters responded that if the first-in-the-nation primary were held today, they'd support Carson.

That's up 12 points from Monmouth's July poll of the Granite State. It puts him 6 points ahead of the third-place candidate, Ohio Gov. John Kasich (R), who nabbed 11% in Monday's poll.

The poll also shows that Carson has lots of room to grow.

His image is far more positive than most other candidates - 73% of Republicans said they hold favorable opinions of Carson, while only 10% view him in a negative light. He's also the top second-choice candidate among New Hampshire Republicans.

Carson's gains since the first Republican presidential debate seemingly haven't been lost on Trump. The real-estate mogul has recently escalated his attacks on Carson, saying he does not have the "energy" necessary to be president.

"He's surging, but he's way behind me," Trump said of Carson.

"I don't think Ben has the energy," Trump continued. "Ben is a nice man, but when you're negotiating against China and you're negotiating against these Japanese guys that are going to come against you in waves, and they think we're all a bunch of jerks 'cause our leaders are so stupid and so incompetent and so inept, we need people that are really smart, that have tremendous deal-making skills and that have great, great energy."

Trump and Carson are both benefiting from a clear trend toward non-establishment candidates among Republican voters, as the Monmouth poll displays.

The vast majority of Republican voters in the Granite State are seemingly uninterested in established politicians - Monday's poll showed that 68% of Republican voters preferred the next candidate to come from outside of government.

This is particularly bad news for more establishment-minded candidates like former Florida Gov. Jeb Bush (R) and New Jersey Gov. Chris Christie (R).

Both have poured a significant amount of time into campaigning in New Hampshire, but have so far failed to see their support materialize. Bush's support, for example, has dropped to 7% support from 12% in July, putting him in a tie for fifth place. Christie's support, meanwhile, is down to just 2%.