Pete Buttigieg’s surge since mid-March from an extreme longshot for the Democratic presidential nomination to one of the leading contenders surprised a lot of people – including the candidate himself.

“We were expecting at this stage of the game to still be introducing ourselves and even defending the idea that something this audacious was appropriate,” Buttigieg told Fox News. “Instead we find that we’ve bolted into the top tier.”

WATCH PETE BUTTIGIEG AT THE FOX NEWS TOWN HALL ON SUNDAY AT 7 PM

It was just two months ago that Buttigieg was still explaining how to pronounce his name. That explanation is rarely needed anymore as the candidate prepares for a Fox News town hall Sunday evening in New Hampshire. He’s seen his poll numbers skyrocket, his fundraising flourish and his national media appearances – as well as the crowds at his campaign events – multiply.

Not bad for a candidate who came into the race with name recognition that paled compared with his more famous rivals, such as former Vice President Joe Biden and two-time White House contender Bernie Sanders, along with well-known senators like Elizabeth Warren, Kamala Harris and Cory Booker. As the two-term mayor of South Bend – only the fourth-most-populous city in Indiana – Buttigieg thought it would take longer to get to this point.

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“The trajectory’s pretty crazy,” he admitted. “Our plan was that we’d be spending the spring and summer just getting our name out there.”

His challenge now – turn the surge of the past two months into a formidable campaign and make the momentum last.

“We’ve got a lot of work to do, blocking and tackling work on the ground, the field organizations we’re building up in the early states and that’s what’s really going to decide whether we can win beginning with the first votes that happen early next year,” he said.

Buttigieg’s campaign quickly outgrew their first headquarters – located in South Bend – and last month moved into a larger facility. The campaign told Fox News that as of a few days ago, there were 60 staffers at the headquarters and in the early voting primary and caucus states.

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The mayor, an Afghanistan War veteran who if elected would become the first openly gay president in America’s history, acknowledges “that initial spike is going to level off and we’re going to be working to maintain a strong position but most importantly put the organizing behind it, so that we’ve got the people on the ground, the field organizers…that’s what really gets you in good shape.”

With so much buzz surrounding his campaign so early, Buttigieg risks running his course in the spotlight before primary voting begins -- a complication Beto O'Rourke, whose media darling status landed him on the cover of Vanity Fair before he even announced but who has struggled lately in the polls, knows all too well.

President Trump, for his part, has sought to knock Pete down a peg, nicknaming him after Mad magazine mascot Alfred E. Neuman and suggesting he'd fall flat negotiating on the world stage with rivals like China.

Buttigieg says he isn’t letting the newfound attention go to his head.

“We’re not fooling ourselves. It’s not like I’m in first place, and most people who don’t follow the blow by blow in this race don’t even know what my message is,” he said.

Part of the strategy is reaching out to voters in places where Democrats don’t always tread.

Ahead of the Fox News town hall, he said, “I’m worried that viewers of Fox will not even understand what that Democratic message is if we don’t have Democratic candidates going on in order to deliver that message.”

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He added, “We’re talking about a news outlet that reaches millions of Americans who may not be as exposed to our viewpoint as viewers of others networks. That’s makes it to me all the more important for us to have a presence there.”