Columbia, South Carolina (CNN) -- After riding into South Carolina on a wave of seeming inevitability, Mitt Romney was dealt a series of blows here that culminated with a disappointing second-place finish in the state's high-stakes primary.
Even before losing to Newt Gingrich by a large margin Saturday night, Romney's team began to look ahead to Florida, where the campaign hoped a big lead in fundraising and on-the-ground organization could help him regain his momentum.
In a speech to supporters here on Saturday, the former Massachusetts governor hit his rivals harder than in any other high-profile speech he has given this cycle.
"We cannot defeat [President Barack Obama] with a candidate who has joined in that very assault on free enterprise," he said in a clear assault on Gingrich, who has criticized Romney's private sector experience at a private equity firm. "When my opponents attack success and free enterprise, they're not only attacking me, they're attacking every person who dreams of a better future."
Romney added: "He's attacking you. I will support you."
Romney's fall in the polls in South Carolina was dramatic and lightning-quick, as Gingrich surged in the last few days before votes were cast. Analysts attributed the former House speaker's rise in part to a well-received debate performance Thursday.
But Romney also suffered setbacks, including the news that updated vote totals showed he had in fact lost Iowa's caucuses to Rick Santorum. He also struggled to answer repeated questions about his tax returns, which he eventually said he would release in April.
The aggressive response Saturday was the sort of thing Romney's supporters would have liked to see earlier, while his rivals were attacking him.
Supporters and donors both in South Carolina and nationally were grumbling Saturday that Romney¹s campaign badly mishandled how he responded to rivals' assertions that he release his tax records and that might have cost him the race.
While there was probably little that he could have done to stop Gingrich's momentum, four straight days of awkward answers on the tax issue kept the campaign from driving any message against Gingrich.
South Carolina's large complement of evangelical and conservative voters had long been considered difficult for Romney to attract, but after winning in New Hampshire he moved onto the Southern state with wide support.
He was joined at many campaign events by the state's governor, Nikki Haley, whose endorsement had been highly prized.
However, Romney's support dipped in the 72 hours before South Carolina's vote. An ARG poll released Saturday morning showed Romney down 6 points since Thursday and Gingrich up 7 points.
Romney was headed immediately to Florida, where he will speak at a rally Sunday in Daytona Beach. He'll participate in two debates there, one on Monday and the CNN/Republican Party of Florida debate on Thursday.
The state votes January 31.