By Jane Sutton
MIAMI (Reuters) - Newt Gingrich struggled to regain momentum in the race for the Republican U.S. presidential nomination on Friday as another poll showed him falling behind his main rival Mitt Romney, who was seen as the winner of the final debate before the Florida primary.
The two men courted Florida's sizable Hispanic vote, many of them Cubans, with appearances on Friday at the Hispanic Leadership Network where Romney received an unusually warm reception and the reaction to Gingrich was more sedate.
Bouncing back from losing the South Carolina primary on Saturday, Romney has a 9-percentage point lead over Gingrich in Florida, according to the Quinnipiac University poll.
That margin was similar to three polls on Thursday.
Quinnipiac pollster Peter Brown said Romney appeared to be pulling away in Florida, where he enjoys a financial and organizational advantage over Gingrich. Romney battered the former House of Representatives speaker in two debates this week, wounding him in the format that has helped fuel Gingrich's campaign.
"With the debates now over, Gingrich will need some other way to reverse the tide that appears to be going against him," Brown said.
Tuesday's Florida primary is the fourth contest in the state-by-state battle for the Republican nomination to challenge President Barack Obama, a Democrat, in the November 6 U.S. election.
Romney repeatedly attacked Gingrich at the Thursday debate in Florida, scoring points on immigration, candidates' finances and even lunar exploration.
"That was Romney on Red Bull," Republican strategist Ron Bonjean said. "You could tell Newt was tired, he's carrying a heavy load. He was counting on pure momentum to carry him through Florida, and that momentum has stopped."
Romney, whom Gingrich has described as the most anti-immigrant candidate in the Republican race, won several standing ovations from the Hispanic crowd in Miami on Friday.
"There is a time coming soon when Cuba will be free," Romney told them, adding "America can't sit back" in dealing with the island nation off the coast of Florida.
GINGRICH CROWD MUTED
Gingrich received a much quieter response, once again mocking Romney's call for "self-deportation" of illegal immigrants as "a fantasy. It's not a solution."
Gingrich said the concept might work for younger illegal immigrants who had been in the United States a short time, but not for older immigrants with deep family ties. They should be allowed to apply for citizenship through local councils similar to draft boards, he said.
A Florida win for Romney would put him in a strong position to capture the nomination - the primary map will tilt in his favor in February with contests in seven states where he has the potential for strong showings.
Next up on February 4 is Nevada, where Romney won with 51 percent of the vote during his failed 2008 presidential bid. On February 7 Minnesota and Colorado hold caucuses and Missouri holds a primary. Gingrich did not make the ballot in Missouri.
Four of the states with February contests - Nevada, Maine, Colorado and Minnesota - use caucus systems, which often require greater organization to rally voter turnout. That could help Romney take advantage of his superior financial and staff resources.
On February 28, Michigan and Arizona hold primaries. Romney was raised in Michigan, where his father was a governor and car executive.
A new pro-Gingrich television ad in Florida asked: "What kind of man would mislead, distort and deceive just to win an election?"
"This man would be Mitt Romney," the ad's narrator said.
Romney's camp said the sharp tone from Gingrich was a sign he was desperate to distract from his own record as House speaker, where he faced an ethics probe, and as a consultant with mortgage giant Freddie Mac.
"It is laughable to see lectures on honesty coming from a paid influence peddler who suffered an unprecedented ethics reprimand, was forced to pay a $300,000 penalty, and resigned in disgrace at the hands of his own party," Romney spokeswoman Andrea Saul said.