U.S. Republican presidential candidate Mitt Romney
Republican primary front runner Mitt Romney. Reuters

(Reuters) - A confident Mitt Romney solidified his lead in Florida polls and ridiculed Republican rival Newt Gingrich, calling his opponent's attacks sad and painfully revealing the day before the state's crucial presidential primary.

Romney's self-assurance was on full display during a campaign tour that felt at times like a victory lap, with the front-runner telling a crowd of about 2,000 in Dunedin, Florida: With a turnout like this I got a feeling we might win tomorrow.

Romney has a double-digit lead in most polls in the state. He said voters have responded to his more aggressive criticism over the past week of Gingrich's work for mortgage giant Freddie Mac, his ethics probe and his resignation as House of Representatives speaker.

There's no question that politics ain't bean bags, and we have made sure that our message is out loud and clear, Romney said on NBC's Today show.

Gingrich, hit hard by the more aggressive Romney strategy, branded his rival as a party insider and elite friend of Wall Street while pledging to stay in the presidential race for the long haul no matter what the outcome in Florida.

On big philosophical issues, he is for all practical purposes a liberal and I am a conservative and that's what this fight is going to be about all the way to the convention, Gingrich said of Romney on CBS This Morning.

Romney shrugged off the attacks, drawing cheers from the crowd when he said Gingrich was not doing too well and had been flailing about.

I know, it's sad isn't it? Romney said, calling it painfully revealing and adding: You've just gotta shake your head.

The bitter back-and-forth in Florida was hardly surprising after two turbulent weeks in what is widely considered the most volatile Republican race for the White House in recent memory.

Just 10 days ago, Romney was limping out of South Carolina, where he came in second. Now Florida is his for the taking after prominent conservatives and party leaders threw their weight behind him, worried a Gingrich nomination would doom Republicans in November's general election against President Barack Obama.

Gingrich said heavy spending by Romney, a former Massachusetts governor, and the Super PAC that supports Romney had killed the momentum Gingrich built with a double-digit win over Romney on January 21 in South Carolina.

He can bury me for a very short amount of time with four or five or six times as much money, most of it raised in Wall Street from the guys who got bailouts from the government, Gingrich said on ABC's Good Morning America.

A Reuters/Ipsos poll released late on Monday showed Romney had edged up to 43 percent among likely voters in Florida's primary, from 42 percent on Sunday. Support for Gingrich slipped to 28 percent from 30 percent a day earlier, 32 percent on Saturday and 33 percent on Friday.

Other polls also have shown Romney opening up a double-digit lead on Gingrich, although a few suggest the result could be more of a nail-biter than expected on Tuesday night.

'JUST GETTING STARTED'

The Gingrich campaign worked to spread the idea that he was staying in the race long-term. Our capacity to tell the truth about Romney's record is limitless. We will challenge Mitt Romney and his lies in every state in every contest, said Gingrich spokesman R. C. Hammond.

At least 1,114 delegates are needed to secure the Republican nomination in August. Florida is the largest state to hold a presidential primary so far this year, and 50 delegates are at stake in a winner-take-all format that will decide who faces Obama.

Baker said even if Romney wins in Florida it will give him just 7 percent of the delegates needed to claim the nomination. The next contest after Florida will be Nevada on Saturday, followed by Minnesota, Colorado and Missouri on February 7.

There is a long way to go before either candidate clinches the nomination, and this campaign will continue for months, he said. The campaign is shifting to a new phase where opportunities are not limited to a single state.

Talking to reporters on Monday, Romney noted Gingrich's growing interest in the campaign's long haul.

That's usually an indication that you think you're gonna lose. When you say 'I'm gonna go on no matter what happens,' that's usually not a good sign, Romney said.

Gingrich said opposition to his candidacy by Republican Party insiders was a badge of honor and a sign of how threatening his candidacy was to the elite.

They recognize I'm a genuine outsider. I know a lot about Washington having served as speaker but have none of the establishment ties and I will shake the system up. They don't want to be shaken up, he said on CBS.

Both candidates crisscrossed Florida in a final hunt for votes on Monday. The two other remaining Republican contenders, former U.S. Senator Rick Santorum and U.S. Representative Ron Paul, are looking beyond Florida to the next races in Nevada, Minnesota, Colorado and Missouri.

Gingrich was introduced at an afternoon event in Tampa by former presidential rival Herman Cain, who dropped out of the race in November after allegations of sexual harassment and marital infidelity. Cain endorsed Gingrich on Saturday.

He's the only candidate that talks about and supports the idea of throwing out the tax code in order to get jobs going in this country. Throw it out! Cain told the crowd.

When Gingrich took the stage, he prompted the crowd to chant 9-9-9 - Cain's frequently cited plan to reform the tax code. You just made his entire day, Gingrich said.