Photo credit: Gage Skidmore.

Former Republican presidential candidate and New Jersey Gov. Chris Christie endorsed current front runner Donald Trump on Friday.

“I am proud to be here to endorse Donald Trump for president of the United States,” Christie said at a press conference. “The best person to beat Hillary Clinton on that stage last night is undoubtedly Donald Trump.”

[RELATED: GOP Debate: Without Rand Paul Present, Chris Christie’s Assad Comments Go Unchallenged]

Christie also referred to Trump’s rival, Senator Marco Rubio (R-Fla.), as “desperate” following Thursday night’s presidential debate.

While CNN described Christie’s move as a “surprise endorsement,” PolitickerNJ reported on Monday that an anonymous source said that Christie “should endorse Trump now— as soon as this week— in order to make himself that first key establishment player to legitimize the tycoon and set himself up as a forward-thinking ally in the Trump camp.”

Jon Ward of Yahoo Politics wrote that he had asked Christie, 24 hours before Christie ended his campaign, why he refrained from going after Trump during a debate ahead of the New Hampshire Primary. While maintaining he could have effectively attacked Trump during that debate, Christie said, “I do so at a time and place of my choosing. There’s no need for me to do that now.”

“Listen, there were plenty of people shooting at Donald over the course of this time, and I wanted to focus on— when the campaign came into real focus— who I had to take on,” said Christie. “The guy I needed to take on in New Hampshire was Marco Rubio.”

[RELATED: Christie Condemns ‘Civil Liberties Extremists’, Argues To Maintain NSA Surveillance In NH Speech]

Christie had, however, criticized Trump in January, describing him as a “thirteen-year-old” for choosing to not attend a debate hosted by Fox News.

“What’s that tell you about what we can expect if things go sideways when you go into the Oval Office? What are you going to do? Go upstairs to the residence and say I’m not playing?” he said. “You know, Vladimir Putin isn’t being nice to me, I’m not going to return his call? The press isn’t being nice to me, I’m not going to hold any more press conferences?”

Last August, Christie told Fox News that “Donald’s a great guy and a good person. But I just don’t think that he’s suited to be president of the United States.”

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