Former Florida governor Jeb Bush speaks during a campaign stop in Derry, N.H., on Jan. 5. (AP Photo/Charles Krupa)

MEREDITH, N.H. -- Republican presidential candidate Jeb Bush, who once enjoyed a wide lead in New Hampshire, has singled out a rival that his team now sees as an immediate threat: New Jersey Gov. Chris Christie.

In an exclusive interview with The Washington Post on Wednesday night, Bush conceded that the GOP primary here is now a race for the second place behind front-runner Donald Trump.

"Look, Trump’s the front-runner and there’s a jump ball for second with five candidates and that will be sorted out over the next few weeks," he said.

Asked whom he would consider in that five-way race, Bush said himself, Christie, Sen. Ted Cruz (R-Tex.), Ohio Gov. John Kasich and Sen. Marco Rubio (R-Fla.). Trump leads by double digits in the Granite State, according to recent polls that, on average, put Rubio, Cruz, Christie, Kasich and Bush behind him.

With just over a month to go, Christie is currently enjoying a resurgence and a second look among many Republicans in the wake of a widely sought endorsement by the New Hampshire Union Leader, the state's largest newspaper.

Answering a question about how he stacks up against Christie and Kasich, Bush honed in on Christie.

"I’ve got a proven conservative record of reform and we need to reform Washington. If past is prologue, why wouldn’t you go with the guy who did the big things?" he said. "It wasn’t simple to take on the teacher’s union and beat ‘em. To create the first and second and third statewide voucher programs in the country or eliminate affirmative action and replace it with a more successful model or cut taxes every year and go from double-A to triple-A bond rating."

New Jersey's credit ratings has been downgraded nine times during Christie's tenure due to shortfalls with the state's pension system.

"Our pension was never raided to pay for the current obligations," Bush added. "We actually put constraints on making sure that the employer portion of the pension obligations was always funded. We put a reserving policy in that when I left, my successor had $9.5 billion of reserves – not many politicians do that except for committed conservatives with a proven record."

A super PAC backing Kasich has also started mailing New Hampshire Republicans fliers that raise doubts about Christie's fiscal management.

Asked if he was trying to raise a broader point about Christie's management abilities, Bush said: "My broad point is that my record I think is the one that, if you compare the three governors, in spite of their talents, is the best one. And I think independent observers would suggest -- whether it’s education, the commitment to reforming our child-welfare system or the other things that we did that were across the board, our child-support system, our business climate, taking on the plaintiffs’ bar, the teachers union the government unions -- I think people would say without a doubt that I have the best record."

"You don’t have to say bad things about the other guy to make that point," he added. "I’m trying not to do that."

The super PAC backing Bush's campaign is airing television and radio ads across New Hampshire that contrasts Bush's gubernatorial record with Christie and Kasich. The accuracy of the ad by Right to Rise USA has been questioned by fact checkers, but it argues that Bush is better seasoned to deal with crisis management, entitlement reform and national security.

[Fact Checker: Right to Rise Super PAC’s series of misleading claims about Jeb Bush’s record]

For his part, Christie said he welcomes the attacks from rivals.

"I’m just better qualified, I’m better tested, I’m more experienced," he told The Post on Tuesday. "I think the reason they’re coming after me now is because I’m doing well. My message is connecting up here in New Hampshire and so, you know, it’s good to be attacked. It means I’m in the game."

As for his chances of placing second, Bush said Wednesday that "I think we have the best volunteers with the greatest commitment and greatest record and get the candidate a little better, I think we’ll be in good shape."

"That’s irony, it’s a new concept in political life," he added. "I just want to make sure that you knew what it was when I used it."

Bush spoke with The Post before a town hall meeting with more than 200 people here at a resort on the shores of Lake Winnipesaukee. He's in the midst of a three-day swing across the state that concludes on Thursday night at the storied Town Hall in tiny Peterborough.