As he aims to be the last challenger standing against former President Donald Trump in the race for the 2024 Republican presidential nomination, Chris Christie's turning up the volume on two other rivals.

Christie's amplifying criticism of Florida Gov. Ron DeSantis and former U.N. ambassador and former South Carolina Gov. Nikki Haley for not vigorously targeting Trump, who remains the faraway front-runner for the GOP nomination as he makes his third straight White House run.

"Ron DeSantis and Nikki Haley have not made the case against him. They refuse to make the case against him. They’re scared to make the case against him," Christie charged in a Fox News Digital interview on the campaign trail in New Hampshire.

And Christie, a very vocal Republican critic of Trump, touted that "the one thing people say about me is I’m not."

POPULAR GOP GOVERNOR IN A CRUCIAL PRIMARY STATE TEAMS UP WITH CHRISTIE, HALEY AND DESANTIS

Christie, Haley, DeSantis, Ramaswamy, Scott on stage

Former New Jersey Gov. Chris Christie, former U.N. Ambassador Nikki Haley, Florida Gov. Ron DeSantis, businessman Vivek Ramaswamy and Sen. Tim Scott, R-S.C., stand on stage before the third GOP presidential primary debate on Nov. 8. (AP Photo/Rebecca Blackwell)

DeSantis and Haley are currently battling for second place in the latest national surveys in the 2024 Republican race and in the most recent surveys in Iowa, whose caucuses lead off the GOP nominating calendar. 

As Christie runs a second time for the White House, he's once again concentrating most of his time and resources on New Hampshire, which holds the first primary in the Republican schedule and votes second after Iowa. Christie is currently in third place in New Hampshire polls, far behind Trump and slightly trailing Haley.

Christie placed all his chips in his campaign for president eight years ago in the Granite State. However, his campaign crashed and burned after a disappointing and distant sixth-place finish in New Hampshire, far behind Trump, who crushed the competition in the primary, boosting him toward the nomination and eventually the White House. 

CHRISTIE VOWS TO ‘CONFRONT’ TRUMP IF FORMER PRESIDENT DOESN'T DEBATE

Christie became the first among the other GOP 2016 contenders to endorse Trump and for years was a top outside adviser to the then-president and chaired Trump’s high-profile commission on opioids. However, the two had a falling out after Trump’s unsuccessful attempts to overturn his 2020 election loss to President Biden. In the past three years, Christie has become one of the harshest Trump critics in the Republican Party.

Chris Christie in New Hampshire

Former New Jersey Gov. Chris Christie, who's running a second time for the Republican presidential nomination, held a round table discussion with Salvation Army leaders in Derry, New Hampshire, on Nov. 21. (Paul Steinhauser/Fox News)

Christie, who for months has pledged to seek out and confront Trump on the campaign trail, said "I think the one person Donald Trump doesn’t want to have a one-on-one with is me."

"He’s not afraid of Nikki Haley," Christie argued. "And he certainly made his feelings about Ron DeSantis known. He doesn’t look like he’s very intimidated by him. But the fact is, you don’t hear him saying that stuff about me. He doesn’t want to be on that stage with me."

DESANTIS LANDS THE ENDORSEMENT OF A TOP EVANGELICAL LEADER IN IOWA 

Christie teamed up Monday night at a town hall in Nashua, New Hampshire, with Republican Gov. Chris Sununu, who also joined Haley and DeSantis on the campaign trail in the Granite State this week. 

Sununu, a popular governor who's also an outspoken Trump critic, has said he'll make an endorsement in the GOP nomination race sometime after Thanksgiving, and that it's down to Haley, DeSantis or Christie.

Asked about the case he's making to Sununu, Christie told Fox News: "who does he want standing across from Donald Trump when this gets down to a one-on-one? Who does he think can take him on in a direct way? Who’s been saying the same things as Chris Sununu has been saying for the last couple of years about Donald Trump, trying to move the party in a new direction? And I think I’m the person who has the clearest, strongest voice on that."

Chis Christie and Chris Sununu in New Hampshire

Former New Jersey Gov. Chris Christie (right) teamed up with New Hampshire Gov. Chris Sununu (center) at a town hall in Nashua. (Paul Steinhauser/Fox News)

Christie said that he needs to do "well" in New Hampshire's primary to be successful in his long-shot bid for the 2024 nomination. Asked to define what "well" means, Christie answered, "No. I can’t define it. I’ll know it when I see it and we’ll see what it looks like."

"If I don’t think I’ve done well enough, I’d get out," Christie emphasized. "I'm not somebody who’s going to linger here. This is hard work, and you’ve got to get up out of bed every morning and feel like you have a chance to win. And if that moment comes where I don’t feel like I have a chance to win, I’m not going to elongate a campaign just for the sake of doing it."

But he added: "I’m convinced that I’m going to do very well here. And I’m going to be the last one standing against Donald Trump and I’m going to take this right to the convention because he’s going to be convicted of federal crimes of interference of our election process this spring."

CHRISTIE JEERED AS HE TELLS TRUMP SUPPORTERS THEY 'FEAR THE TRUTH' AT FLORIDA REPUBLICAN GATHERING

Chris Christie and Donald Trump

Former Republican New Jersey Gov. Chris Christie told Fox News Digital he believes former President Donald Trump will be convicted of "federal crimes of interference of our election process this spring." (Getty Images)

Trump has made history as the first former or current president to be indicted for a crime, but his four indictments – including in federal court in Washington, D.C. and in Fulton County court in Georgia on charges he tried to overturn his 2020 presidential election loss – have only fueled his support among Republican voters.

Christie's a longtime friend of Sen. Joe Manchin of West Virginia, dating back to their days as fellow governors. Manchin, a moderate Democrat in a heavily red state, announced earlier this month that he wouldn't seek re-election to the Senate next year and instead is mulling a potential third-party run for the White House.

"Joe and I had dinner together about ten days ago in D.C. It was great to see him," Christie shared. "We had a great dinner together on his boat in the Potomac. He’s been a great friend for 14 years now, and I suspect that whatever happens in the upcoming year, we’re going to continue to be great friends."

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But Christie ruled out teaming up with Manchin in any possible third-party presidential bid.

"I’m committed to winning the Republican nomination for president. I have no interest in being a third-party candidate," Christie told Fox News. "Joe can do whatever it is he wants to do. Everyone’s got to make their own decision. My decision is the only interest I have is being the Republican nominee for president because I think that’s the best chance I have to win."

Get the latest updates from the 2024 campaign trail, exclusive interviews and more at our Fox News Digital election hub.