MANCHESTER, N.H. — Conventional wisdom says the Republican presidential contest is a three-man race, with Donald Trump, Ted Cruz, and Marco Rubio the only candidates who still have a chance of winning. But Chris Christie didn't get the memo, and as a result of his strong performance here at Saint Anselm College Saturday night, the Trump-Cruz-Rubio three-man-race theory is still not entirely set in cement.

Christie was loaded for bear in the final debate before the New Hampshire primary. He badly rattled Rubio, repeatedly made the case for executive experience — his own, of course, but also that of the other governors in the race — and effectively belittled the governmental experience, not just of Rubio but also of Ted Cruz, the other first-term senator in the top tier.

In all, Rubio learned it's hard being a front-runner, even a media-anointed front-runner. Your opponents are listening closely and looking for weak spots.

Rubio's weakness appeared on display early in the debate. There's a meme going around among Rubio's critics that he is a "robot," a talking-points machine who says the same poll-tested things over and over and isn't really able to engage issues. (It's not a fair rap — Rubio can be terribly repetitive, as all the candidates can, but he can also speak with some eloquence extemporaneously. But then again, debates aren't about fair.)

Rubio and Christie had engaged in an exchange about the value of experience in a presidential contest. Rubio slammed Christie's record in New Jersey, and then turned his attention to the current occupant of the White House. "Let's dispel with this fiction that Barack Obama doesn't know what he's doing," Rubio said. "He knows exactly what he's doing."

Christie was ready. "That's what Washington, D.C., does," he said in response. "The drive-by shot at the beginning with incorrect and incomplete information and then the memorized 25-second speech that is exactly what his advisers give him."

And then, darned if Rubio didn't repeat the same soundbite. "This notion that Barack Obama doesn't know what he's doing is just not true," he said. "He knows exactly what he's doing."

Christie turned it into an "A-ha!" moment. "There it is," Christie said. "There it is. The memorized 25-second speech. There it is, everybody."

Just for emphasis, Rubio repeated his point a couple more times, as if he wanted to confirm the robot theory once and for all. He didn't look good.

Rubio recovered later in the debate with answers about national security and the nature of conservatism. But over the course of seven previous debates, his advisers had grown used to crowing that he won every one. Not this time. In the spin room afterward, top Rubio aides bragged not that their man conquered all, but that he wasn't lying flat on the canvas.

"What Gov. Christie was trying to do was to knock Marco out, to kill him dead," said key adviser Todd Harris. "He took his best shot, and he failed."

"We came into this debate saying that the goal was to get through it, knowing that you have a bunch of candidates who are in a fight for their life," added another top aide, Alex Conant. "The other candidates came into this debate needing to knock Marco out and have a moment. They failed to knock Marco out, and the best moments of the debate belonged to Marco." Except, of course, that the worst moment of the debate belonged to Marco, too.

For their part, Team Christie was delighted. More than delighted. "Oh man, it was the clearest one yet!" campaign manager Mike DuHaime exclaimed as he walked into the spin room, as if Christie had had a string of victories before but this one was the most decisive. "He's prepared to give one-minute speeches," DuHaime said of Rubio. "He's not prepared to be president of the United States."

DuHaime predicted Christie's performance would pay off in the polls and on election day: "I think he's going to climb quickly after this." Christie will need the boost. Back in late December and early January, he was in the low double digits in the RealClearPolitics average of New Hampshire polls. Then, as January went on and the political world's attention focused on Iowa — Christie himself made a swing or two there — Christie began a slow slide in the Granite State. Now, he's about five percent in the RCP average. Even if he does get a much-needed jolt from the debate performance, there's almost no time to take advantage of it before Tuesday.

Still, Christie had about the best night he could have had. And, by the way, fellow governors Jeb Bush and John Kasich had pretty good evenings, too — so much that ABC's Jonathan Karl called the debate "the revenge of the governors."

The other leading candidate, Ted Cruz, had only a so-so night. But that was fine with him. In a conversation before the debate, Team Cruz suggested the event "could absolutely be a game-changer for somebody" — but that person would not be Cruz. "We're not winning, so we don't need to hit a home run," a Cruz aide said. And so he didn't hit one. Or even a double.

One final candidate had a very good night: Donald Trump. The New Hampshire front-runner — with a lead at 14 points and shrinking, according to the RealClearPolitics average of polls — made a self-defeating decision to skip the last debate in Iowa, but in Manchester Saturday night, Trump was strong. "He did his best of the eight tonight," said new Trump adviser and former Ben Carson campaign manager Barry Bennett. Trump's solid performance could remind New Hampshire voters why they liked him so much.

How well did Trump do? Well, at times, even his rivals sounded downright Trumpian. "When I'm president of the United States, we are going to re-embrace all the things that made American the greatest nation in the world," Rubio said early in the debate. It's not an original thought, nor headline-making one. But a pithier way of saying it, of course, would be "We are going to make America great again."