New Jersey Gov. Chris Christie endorsed GOP presidential front-runner Donald Trump on Friday, the latest sign that Republicans are beginning to accept the idea that the real estate magnate may win the party's nomination.

"I am proud to be here to endorse Donald Trump for president of the United States," Christie said at a news conference alongside the businessman, explaining that he has been friends with Trump for over a decade. "I absolutely appreciate him as a person and as a friend."

But the endorsement extended beyond the personal, and Christie said he believed that "there is no one who is better prepared to provide America with the strong leadership that it needs, both at home and around the world, than Donald Trump." Among the field of GOP candidates — which also includes Florida Sen. Marco Rubio, Texas Sen. Ted Cruz, Ohio Gov. John Kasich, and retired doctor Ben Carson — Trump is "the clear standout, and the person who will do exactly what needs to be done to make America a leader around the world again," Christie said. In fact, Christie said establishment favorite Rubio is "desperate" and that his attacks on Trump during Thursday's debate would not succeed: "Nobody is going to get inside this guy's head," Christie said of his presidential pick. "Senator Rubio has shown himself over the course of time to be wholly unprepared to be president of the United States," Christie said — just as many pundits and GOP notables had begun to rally around the senator as Trump's primary competition.