TAMPA, Fla. - Mitt Romney was desperate for a strong debate performance in Florida's Republican debate Monday night to restore momentum for his campaign, and delivered repeated sharp attacks on rising rival Newt Gingrich.Romney lashed out at Gingrich at the Florida debate for resigning as speaker of the US House of Representatives under an ethical cloud and repeatedly labeled him an "influence peddler."RELATED:Gingrich wins South Carolina GOP primaryThe former Massachusetts governor needs a victory in the state's primary on Jan. 31 to win back his front-runner status in the fight for the nomination to oppose US Democratic President Barack Obama in November's general election after Gingrich's convincing victory in South Carolina on Saturday.Often lukewarm in earlier debates, Romney kept on message by seeking repeatedly to tar Gingrich as a Washington insider who lobbied for clients including the troubled mortgage giant Freddie Mac."In the 15 years after he left the speakership, the speaker has been working as an influence peddler in Washington," Romney said.Gingrich shot back that Romney was not telling the truth. "He's said at least four things that are false," he said.Romney took a much tougher tone than he did last week during a debate in South Carolina, when he stumbled in response to questions about his tax records. "I learned something from that last contest in South Carolina, and that was I had incoming from all directions, was overwhelmed with a lot of attacks. And I'm not going to sit back and get attacked day in and day out without returning fire," Romney said.