Sen. John McCain has defeated former Gov. Mitt Romney in the coveted GOP Florida primary, sending him to next week's critical Feb. 5 multistate battle a bona fide Republican front-runner.
This is McCain's third primary win, having garnered victories in New Hampshire and South Carolina, but the first in a Republicans-only contest that excluded independent voters.
Just a few months after his campaign was all but dismissed and was struggling in polls on reports of lackluster fundraising and staff shake-ups, the Arizona senator now has national momentum.
"Our victory may not have reached landslide proportions but it is sweet nonetheless," McCain told cheering supporters at a rally in Miami, who yelled "Mac is back!"
"This was a hard-fought election that was worth fighting hard for," he said.
"My friends, in one week we will have as close to a national primary as we've ever had in this country," he said. "I intend to win it and be the nominee of our party."
McCain's victory in the Sunshine State earns him all of Florida's 57 delegates, making him the Republican with the most delegates so far in a race looking increasingly like a delegate-war.
Former New York Mayor Rudy Giuliani came in third, and former Arkansas Gov. Mike Huckabee placed fourth.
The outcome is a crushing blow to the presidential aspirations of Giuliani, who gambled his entire campaign on winning the Florida primary, effectively skipping the earlier state contests.
"It not over until it's over," Giuliani told supporters at a rally in Orlando, repeating the comment back to someone who first yelled it from the crowd.
"Like most Americans, I love competition. I don't back down from a principled fight," Giuliani said.
"The responsibility of leadership doesn't end with a single campaign. If you believe in a cause, it goes on and you continue to fight for it and we will," he said to cheers from the crowd.
However, ABC News' Jake Tapper reports Giuliani will board a plane to California tomorrow morning, as planned. But sources told ABC News that once there, instead of participating in the GOP debate, he will drop out of the presidential race and endorse McCain.
McCain was generous in praising Giuliani during his victory speech.
"I want to thank my dear friend Rudy Giuliani who invested his heart and soul into this primary and who conducted himself with all the qualities of the exceptional American leader he truly is," McCain said tonight.
On the Democratic side, Sen. Hillary Clinton won the Florida contest, with Sen. Barack Obama coming in second and former Sen. John Edwards taking third place.
"This has been a record turnout, because Floridians wanted their voices to be heard," Clinton told supporters at a rally in Davie, Fla.
"I promise you that I will do everything I can to make sure not only are Florida's Democratic delegates seated but that Florida is in the winning column for Democrats in 2008," she said.
The contest was widely considered simply a beauty contest because no delegates were up for grabs. The Democratic National Committee stripped Florida of its delegates as punishment for moving its primary date up to January and the candidates maintained a pledge not to campaign there.
Despite that, the Clinton campaign has argued in recent days that Florida is an important test because of the state's large and diverse population, including a sizable Hispanic community.
"We don't envision a circumstance in which the Democratic National Convention doesn't seat delegates from Michigan and Florida," Clinton campaign Communications Director Howard Wolfson said on a conference call with reporters Tuesday afternoon, reports ABC News' Eloise Harper. "We know at the end of the day these delegations are going to get seated."
McCain's win has also taken the wind out of Romney's sails, although Romney remains in the stronger financial position and is able to fund costly television ads in Super Tuesday states.
Romney, who has already spent $17 million of his own fortune on his White House bid as of Sept. 30, made a joke during his concession speech about it.
He told the crowd they all felt like family, but "don't expect to be part of the inheritance … not sure there is gonna be much left after this."
A Romney campaign aide told ABC News' John Berman that McCain's win in Florida is due, in part, to "McCain's superior name ID" but emphasized that now there is a two-man race going into Super Tuesday.
In recent days, McCain also won key endorsements by Florida Sen. Mel Martinez and Florida's Republican Gov. Charlie Crist.
"We were on track to win after the debate and McCain knew it," a Romney adviser told Berman. "Martinez and Crist changed [the] dynamic."
The Romney aide also says McCain's negative campaign tone this weekend took a toll. McCain "got dirty at the end," said the Romney adviser. "He got negative and nasty."
McCain and Romney have waged an acrimonious battle against each other for the Sunshine State, with Romney painting McCain as a Washington insider with liberal Democratic policies, and McCain describing Romney as a serial flip-flopper who has moved to the right on multiple issues since announcing his presidential bid.
McCain's claim Saturday that Romney supported Democratic plans for a specific date for troop withdrawals from Iraq threw Romney off his message, Berman reports. He seemed angry, and ended up playing for a day in McCain's "wheelhouse."
Exit polls suggest veterans turned out in large numbers, which may have benefited McCain, who touted his credentials as a veteran and a war hero.
Going into next Tuesday's multistate contest, McCain now has 95 delegates; Romney, 59; and Huckabee, 40. A candidate needs 1,191 delegates to win the GOP nomination. The Arizona senator also has bragging rights for having won the largest and most diverse state to vote so far. The momentum will be critical going into Feb. 5, when more than 20 states will vote, including California, which has 370 delegates up for grabs.
"The winner comes to California on a rocket ship," said Dan Schnur, a California-based Republican analyst who is unaffiliated with any campaign but worked as McCain's communications director during the 2000 primary.
All the leading Republican candidates are scheduled to appear at a Republican debate in California Wednesday night, including Giuliani, whose campaign status appears uncertain.
Earlier this week, McCain and Romney repeatedly blasted one another. Romney said McCain would set the nation on a "liberal Democratic course," while McCain said Romney's campaign is based on the "wholesale deception of voters."
At a polling station in St. Petersburg, Fla., this morning, McCain took some last digs at Romney when asked about the rising level of vitriol between the rivals.
"It's only been Gov. Romney who decides to attack opponents when he thinks they are moving up and succeeding," McCain said, reports ABC News' Bret Hovell. "That's just the way he campaigns; it's just a matter of record."
Asked how he was feeling, McCain touted his endorsement from Florida's Republican governor, Charlie Crist.
"I'm feeling good. Endorsements matter," McCain said. "It would have been very easy for Gov. Crist to say, 'I'm not going to get into a contested primary.' I'm very grateful and very appreciative."
Romney kept up his attack on McCain Tuesday but didn't mention him by name.
"One of the candidates out there running for president said that the economy is not his strong suit. Well, it's my strong suit," Romney told supporters at a campaign rally in Tampa, Fla., reports ABC News' Matt Stuart.
"I think it's helpful to have a president of the United States who actually has been in the real economy if he's gonna try and fix the real economy," Romney said, continuing his strategy of touting his business credentials.
Preliminary exit poll results suggest the economy emerged as a top concern for Republican primary voters in Florida, as it has throughout this primary season. About 40 percent of voters said they were looking chiefly for a candidate who "shares my values" and just over 30 percent said they wanted a candidate who "has the right experience."
Former Gov. Mike Huckabee, who has yet to repeat his win in Iowa, has said he is trying to stay in the race until Feb. 5, where he may be in a better position to wage a delegate war with his rivals.
"It's an important vote just to keep us in the game. We know that right now going into today that we may not be leading in the polls, but we expect to come out of here still on our feet, and that's what's important to us," Huckabee said today in Tampa, reports ABC News' Kevin Chupka. "Next week, when we have a lot of Southern states in play and we're leading in all those states, it's going to be a really big day for us to pick up delegates."
Going into the Feb. 5 races with a strong campaign was seen as important because of the cost of competing in more than 20 states.
"No one, not even Mitt Romney, can afford saturation advertising across California and 20 other states all at the same time," Schnur said. "So while Romney will have a significant paid-media advantage, a win for McCain in Florida would largely erase that in terms of the news coverage and public attention he'd be getting."
ABC News' John Berman, Peyton Craighill, Jake Tapper, Rick Klein, Jan Simmonds, Bret Hovell, Kevin Chupka, Eloise Harper and Matt Stuart contributed to this report.