Florida Gov. Charlie Crist endorsed John McCain Saturday night for the GOP presidential nomination.

The much-coveted announcement came for McCain at a dinner in St. Petersburg, Fla., held in advance of Tuesday's competitive primary. McCain and Mitt Romney have been butting heads in the Sunshine State over everything from economic knowledge, leadership credentials to their positions on the Iraq war. The endorsement is also a blow to Rudy Giuliani, who had been courting Crist heavily over the last several months.

"As you know we have a very important election here in Florida come Tuesday ... and the man who stands next to me is really a true American hero, he is a great United States senator ... I think the world of him, and we have a lot of great people who are running for president this year who would do well. I have been thinking about it a lot, and I have to tell that after thinking about it as much as I have, I don't think anybody would do better than the man who stands next to me, Senator John McCain. That's an endorsement," Crist said after calling McCain to the stage with him.

McCain met with Crist Saturday afternoon, according to a source in the governor's office, which issued a statement saying, McCain "is a patriot, a true hero and the best person to lead this country."

McCain said the nod "means a lot in this race."

"I'm honored and privileged," McCain told reporters. "And I intend to work very closely with him on the issues. We've got to provide home insurance for every person who lives in the path of a hurricane. We are going to have to work together to save the Everglades and other great environmental treasures of this state."

Romney and Mike Huckabee had also been courting Crist.

Crist is popular with Florida Republicans, but former Gov. Jeb Bush is also a stand-out among the base. In an e-mail to The Associated Press, Bush said he respects the governor's decision, "but Republican voters will determine who they want among very fine candidates. I look forward to working for our party's nominee in the general election."

Crist's endorsement does follow a Friday announcement in support of McCain by Florida's Republican Sen. Mel Martinez.

"John McCain is the only candidate ready to lead as commander in chief on day one. He alone has the experience, character and judgment to confront the challenges we face in a dangerous world. He is the one candidate I trust to deal decisively with the transcendent threat of radical Islamic extremism," Martinez said.

According to the RealClearPolitics average of recent GOP polling in Florida, McCain is leading the field 26.3 percent to Romney's 26 percent, with Giuliani in third with 17.7 percent. Mike Huckabee has 14.6 percent in that average and Ron Paul is at 4.7 percent.

The Associated Press contributed to this report.