"I expect to win it," he said. "You don't contemplate losing it. That isn't something you do on the day of a primary."
Polls show the former New York mayor, last year's national front-runner, trailing badly in the state where he has poured most of his time and energy in his pursuit of the Republican presidential nomination. If he wins Florida, he will have earned the biggest, brashest "I told you so" of his political career.
Lose, and Giuliani may be uttering his final words of the campaign.
"Wednesday morning, we'll make a decision," he told reporters between campaign appearances Monday. "The winner of Florida will win the nomination; we're going to win Florida."
Pressed to elaborate on that remark during morning TV appearances Tuesday, Giuliani declined to go further.
"We are going to win," he insisted. "Of course if you don't win you figure out another strategy"
Just last week, he insisted that no matter what the outcome in Florida he would continue running.
"In the past, I've done the impossible - things that people thought were impossible," he told supporters at a rally Monday. He was talking about immigration policy at the time, but he might as well have been discussing how to resuscitate his presidential campaign.
In an unconventional move, Giuliani largely bypassed the early voting states of Iowa, New Hampshire, Michigan and South Carolina, pinning his hopes on a fractured field and the prospect that his moderate GOP record would attract support in the delegate-rich states of Florida, New York, California and Illinois.
Florida has been less than hospitable. Surveys show rivalsand fighting for the lead, and the state's top two Republicans - Sen. Mel Martinez and Gov. Charlie Crist - endorsed McCain.
Giuliani was the early favorite among Republicans last year, due to his larger-than-life role leading New York after the Sept. 11 attacks. But his early lead evaporated and he finished sixth in Iowa, fourth in New Hampshire.
He has settled on an all-or-nothing Florida strategy, and if he cannot pull off the upset, he will have scant support or resources left to compete with McCain or Romney in next week's 20-plus primaries and caucuses.
His poll-opening remarks Tuesday came on NBC's "Today" and ABC's "Good Morning America."