Sen. Marco Rubio (R-Fla.) with his kids after addressing supporters at his caucus-night party Monday in Des Moines. (Pete Marovich/Getty Images)

Marco Rubio’s surprisingly strong showing in the Iowa caucuses reshuffled the already intense competition here in New Hampshire among the Republican establishment candidates, leading some to sharpen their attacks on the freshman senator from Florida ahead of next week’s primary.

The sense of urgency was on display here Tuesday as New Jersey Gov. Chris Christie belittled Rubio’s toughness, his intelligence and even his manhood.

“Maybe he’ll do more than 40 minutes on a little stage telling everybody his canned speech that he’s memorized,” Christie said to reporters, mocking Rubio’s tightly controlled campaign appearances. “This isn’t a student council election, everybody. This is an election for president of the United States. Let’s get the boy in the bubble out of the bubble.”

Former Florida governor Jeb Bush, meanwhile, expanded his line of attacks beyond Donald Trump to include Rubio and Sen. Ted Cruz (Tex.), the winner of Monday night’s Iowa contest. Bush said at a town hall meeting in Rindge that Rubio, 44, and Cruz, 45, did not have the “life experience” to be president and questioned whether either had ever sacrificed his personal ambition for the public good.

For the past six weeks, the four mainstream GOP candidates — also including Ohio Gov. John Kasich — have looked to New Hampshire as their proving ground. But the calculus of all four was changed by Iowa, where the three with gubernatorial experience each finished in low single digits while Rubio surged to within one percentage point of Trump, who came in second.

The Fix's Chris Cillizza explains where Bernie Sanders, Ted Cruz and other presidential candidates stand after Iowa's caucus and what's next going into the New Hampshire primary. (Whitney Leaming/The Washington Post)

With only one week until the New Hampshire primary and the potential that voters here could effectively eliminate some candidates from the nomination battle, the stakes are high and the tone is increasingly confrontational.

“It is a dog-eat-dog, hand-to-hand combat up here,” said Steve Duprey, a Republican National Committee member from New Hampshire. “These guys are going to be scrapping it out until the final minute. At stake is a ticket out of New Hampshire.”

[The inside story of how Ted Cruz outfoxed Donald Trump]

Going all in

In past election years, New Hampshire Republicans have not followed the lead of Iowa in making their choices. Mike Dennehy, a New Hampshire-based GOP strategist, said the dynamics of the race among the establishment candidates here could be affected by the order of finish in the Hawkeye State.

“I think this year is different,” Dennehy said. “There are so many candidates this year that they are looking for help, and I think Iowa did that last night.”

That puts enormous pressure on Bush, Kasich and Christie.

“The establishment candidates who have gone all in in New Hampshire are making their last stand,” said Republican strategist Steve Schmidt. “Bush, Kasich and Christie have to knock Marco Rubio down in New Hampshire and steal his spot for a rationale for their campaigns to exist.”

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But Dennehy said Rubio’s performance in Iowa also heightens the stakes here for the senator. “He has to push those [other establishment] candidates down to get into a strong second-place showing,” he said. “Third place just isn’t good enough for him. You’ve got to show progress and momentum.”

Rubio’s advisers said they are optimistic he will be able to do just that.

“We’re not sneaking up on anybody anymore,” said a senior Rubio campaign official who requested anonymity to talk about the post-Iowa environment. “Folks have figured out that Marco is a candidate who connects with voters and who closes strong. He’s got momentum.”

Rubio returned to New Hampshire early Tuesday, arriving before dawn and visiting a Manchester diner during the breakfast hour. He was upbeat and said he hoped to replicate his Iowa success in next Tuesday’s New Hampshire primary.

[The Fix: The winners and losers of the Iowa caucuses]

When a supporter presented Rubio with some cigars, the son of Cuban immigrants responded playfully.

“Let’s hide them, guys. I used to smoke a little cigar here and there,” he said, adding that he didn’t want to be a bad influence on his young children but that a celebration may soon be in order. “Maybe we’ll save them for Tuesday night,” Rubio said, referring to the Feb. 9 primary.

Prior to Iowa, recent New Hampshire polls showed Bush, Cruz, Kasich and Rubio in a statistical tie for second place, with Christie trailing a few points behind. Trump has long led the field by roughly 20 percentage points.

Last chances?

Next Tuesday’s primary is expected to help winnow the chaotic Republican field, affirming one or two establishment candidates as the consensus choices for party donors and other leaders when the nominating contest heads to a slew of Southern states.

“One of them is going to emerge as the leader here,” said Meg Whitman, the chief executive of Hewlett-Packard and a Republican donor who campaigned with Christie on Tuesday in New Hampshire. “I think there will be a natural winnowing.”

The establishment-friendly candidates are comforted by the fact that many New Hampshire voters tend not to settle on a candidate until days before the primary. Noting that time is running out, Kasich said to laughter at a town hall meeting in Newbury, “All you undecideds, knock it off!”

[Iowa caucus election results]

Sen. Rob Portman (R-Ohio), a Kasich supporter who knows the state from his years at Dartmouth College, said: “New Hampshire attempts to be a place where presidential campaigns get launched. Iowa is important, but when you look at the results over the last several elections, it tends to be New Hampshire winners who go on to the general election.”

Bush, who has been humbled since falling out of the top tier of candidates last year, has labored to mount a comeback in New Hampshire. He is beginning what aides describe as a “dogfight” to finish second to Trump, whom they expect will win the primary.

Bush will lean on the popularity of his mother, former first lady Barbara Bush. He will appear with her on the campaign trail in coming days, and with Columba Bush, his publicity-shy wife, who has been huddling privately with local residents.

A key component of Bush’s strategy here is negative advertising, something for which his aides will not apologize. The campaign said Tuesday it was buying two-minute chunks of television air time for its toughest ad yet against Trump, part of a $4.5 million New Hampshire advertising blitz.

Kasich, meanwhile, vowed Tuesday to stay positive, calling on his opponents to stop airing negative ads and to urge their super PACs to do the same.

“I just think it will work for me by being positive, and I wish all of them would just knock it off and let’s just judge who’s got the best program and the best plan and the best message and the most town halls,” Kasich told reporters in Newbury.

But rivals complain the positive tone does not extend to Kasich’s super PAC, or even to his own operation. Kasich’s chief strategist, John Weaver, said that when Kasich is attacked, the campaign will respond in kind.

Of Rubio, he said, “I’m not going to go as far as Chris Christie, but Rubio’s not somebody that likes the ad hoc atmosphere of campaigns.”

One thing all four campaigns agreed on is that it was anybody’s game — and that New Hampshire voters are predictably unpredictable.

“New Hampshire Republicans are the most powerful people in the world right now, bar none,” Christie said at a town hall meeting in Epping. “You’re going to take this race from 11 candidates probably down to four or five. . . . Exercise it with great care.”

Balz reported from Newbury. Ed O’Keefe in Rindge and Sean Sullivan and Robert Costa in Manchester contributed to this report.