(CNN) Pete Buttigieg's razor-thin lead over Bernie Sanders with all votes now counted in the chaos-marred Iowa caucuses is elevating a rising star of a new generation to the top tier of American politics and sending him roaring into the New Hampshire presidential primary.

The caucuses may have been a debacle that is threatening Iowa's first-in-the-nation status and exposed Democrats to mockery, but they did fulfill one of their core functions: identifying rising candidates, exposing weakness among front-runners and transforming the Democratic presidential race before sending it on to the Granite State.

Going into Friday night's debate, four days before the critical first primary, confrontations are boiling up between rival campaigns. Several major league candidates are already facing existential moments, while President Donald Trump's big week is concentrating minds about the perilous path ahead for Democrats desperate to confine him to a single term.

After their close finish in Iowa, Vermont's Sen. Sanders and former South Bend, Indiana, Mayor Buttigieg may also be offering a preview of a left vs. center showdown in the months to come if they can maintain their momentum and expand their coalitions.

Former Vice President Joe Biden is lashing out at both of them after a poor Iowa showing left him needing a comeback in New Hampshire -- to quell rising questions about his South Carolina firewall -- and the staying power of a once front-running campaign.

And Sen. Elizabeth Warren of Massachusetts, scaling back ad buys after failing to get a cash boost from third place in the caucuses, may have no choice but to provoke a long-delayed clash with Sanders, since her campaign needs to show it can beat him somewhere in order to prolong their battle for progressives.

New Hampshire, meanwhile, brought its own unique flavor to the primary process Thursday, as candidates fielded questions about the Electoral College, the fracking industry, health care, the climate and tax policy across the state, including at a series of CNN town halls

Sanders and Buttigieg both claim Iowa victory

As the race increasingly focuses on New Hampshire, Democratic officials are still trying to clean up the botched vote in Iowa. With 100% of precincts finally reporting, Buttigieg led with 26.2% of state delegates, which determines who wins the contest. It put him a tenth of a percentage point ahead of Sanders, who led in the popular vote.

Warren was third, with 18.0%, ahead of Biden, with 15.8%. Minnesota's Sen. Amy Klobuchar was fifth, with 12.3%.

The Democratic candidates have until 1 p.m. ET (12 p.m. CT) on Friday to file a request for a recanvass or a recount. If no claims are forthcoming, a winner can be declared.

The tortured story of the 2020 caucuses, which critics say should deprive Iowa of its spot at the front of the nominating process, took another twist on Thursday as Democratic National Committee Chairman Tom Perez called for a recanvass of all the votes. But adding to the sense of a party in disarray, the state party said it would do so only if a candidate requested such a step, per the rules of the caucuses.

And a CNN analysis shows errors in the count reported by the Iowa Democratic Party.

Perez sought to promote confidence in the party's ability to conduct a competent primary season in an interview on CNN's "New Day" Friday morning, pledging that Democrats will "learn the lessons of Iowa" going forward.

But the two top finishers in Iowa were already claiming victory Thursday night, adding to the confusion.

Sanders disputed Buttigieg's previous claim that he had walked out of the Hawkeye State on Monday night "victorious" -- laying claim to a win in the popular vote, even though the metric used to score the election is state delegate equivalents, in which Buttigieg has a minuscule lead.

"It is really sad that the Democratic Party of Iowa, if I may say so, screwed up the counting process quite so badly," Sanders said at the CNN town hall.

"We ended up winning the popular vote by 6,000. They have a realignment process, as you know, in Iowa; we won that by 2,500. And I suspect at the end of the day, Mr. Buttigieg and I will have an equal number of delegates at the national convention," Sanders said.

Buttigieg told CNN's Chris Cuomo at the subsequent town hall that it was "fantastic news to hear that we won" and congratulated Sanders and his supporters on their race.

"We're in New Hampshire now," Buttigieg said, mindful of how the Northeastern battleground often delivers a shock to Iowa victors. "New Hampshire is a state that has never been told what to do."

Pushing back against Biden

Sanders and Buttigieg also responded to the new attacks from Biden, whose campaign was revealed by Iowa to be suffering from a series of fundamental deficiencies.

The former vice president warned Wednesday that Sanders would hurt down-ticket Democrats because he is a democratic socialist. And he criticized Buttigieg for what he described as criticism of President Barack Obama's presidency and argued that the 38-year-old lacked the requisite experience to be president.

Buttigieg, the only candidate who exceeded expectations in Iowa, has suddenly emerged as a grave threat to Biden's role as the preeminent centrist in the Democratic race.

He fired off several sharp rebukes to the former vice president, perhaps testing lines ahead of Friday's debate featuring seven candidates in Manchester, New Hampshire.

"If that argument is about electability, and the ability to win, we just had the first election of the 2020 process. And I think that's my answer," Buttigieg said on ABC's "The View."

Biden will find himself in an unusual position at the debate. For most of the preseason in the campaign, the former vice president has been the target of attacks. Now, to prove his campaign has life and to turn around unpromising polls in New Hampshire, he is under pressure to create "moments" that could slow Sanders and Buttigieg.

Biden was off the trail entirely on Thursday -- a potentially wise choice, as it gave him a chance to prepare for the hugely crucial debate.

The Biden campaign is also hampered by its difficulty in raising funds fast -- the former vice president had $9 million in the bank at the end of January. Sanders, by contrast, piled up $25 million in the first month of the year alone from small donors.

A cash crunch not only could hurt Biden going into South Carolina -- the first state where his popularity among black voters could really help -- but it also will shrink his capacity to compete in the nationwide Super Tuesday primary just a few days later.

Sanders hinted at how he might respond to a Biden broadside on Friday night by defending his democratic socialism as analogous to Scandinavian societies with "wonderful" health care and education systems.

"We are proud to talk about the need to create a government that works for all, not just a few. And when Trump talks about socialism, you know, the truth is that Trump is a socialist as well. His socialism is designed to benefit wealthy people like himself," Sanders told CNN's Ryan Nobles.

Like Biden, Warren faces a challenging route in New Hampshire. Her momentum of the late summer now a memory, she is trailing Sanders in the race to become the standard-bearer of the Democratic left wing after Iowa.

She issued a call to supporters for $2 million before Tuesday's primary, signaling that, like Biden, she may be having financial trouble.

Warren's campaign canceled $355,000 worth of advertising reservations that had been placed in Nevada and South Carolina, the next two contests after New Hampshire, according to CMAG data.