Gingrich clearly benefited from a feisty performance in the final TV debate before the primary in which he blasted the CNN host for asking about revelations by his second wife concerning his "open marriage" request that led to their divorce. In contrast, Romney appeared uncomfortable when asked about his tax returns, and refused to shift from his strategy consisting of attacking President Barack Obama as if he had already secured the party nomination.
He was on the defensive when questioned on his business record at the head of private equity firm Bain Capital, and his challengers described him as a "corporate raider" and scion of "vulture capitalism".
After trailing behind Romney in the polls, Gingrich's poll numbers surged after the debate.
South Carolina, a blue-collar state where a majority of voters define themselves as Christian evangelists, was always going to be difficult for Romney, derided as the "Massachusetts moderate" by Gingrich, a southerner who hails from neighbouring Georgia.
But whereas Romney left New Hampshire, the state next door to his own, declaring that he had "made history" by winning two nomination contests in a row, the latest result means that he has in fact only sealed one. That's because a recount in Iowa handed his wafer-thin victory from the January 4 caucuses to his conservative challenger Rick Santorum.
Santorum, a former Pennsylvania senator, came third in South Carolina, while the libertarian Congressman from Texas, Ron Paul, was in fourth place. Paul's Tea Party supporters deserted him in favour of the ultimate Washington insider Gingrich in the belief that he would be best placed to challenge Obama next November.
The race now looks like a contest between Romney - who no longer seems the inevitable choice of a party which had cast around for more conservative alternatives before reluctantly embracing him - and Gingrich.
Both candidates have serious negatives which will be exploited by the Obama campaign. Romney aides have warned that they will go after the thrice-married Gingrich over an ethics reprimand in 1997. And Romney's failure to connect with the average voter has been displayed several times.
Looking beyond South Carolina, the national polls still put Romney 10 points ahead of Gingrich. And they predict that in the election, Obama would win a close race against either Republican candidate. But much will depend on the state of the economy which, the South Carolina vote showed, remains the electorate's number one priority.
The President is busy with a fundraising blitz that raised US$42 million ($52 million) in the last quarter of 2011, eclipsing his Republican rivals. On Friday, he was treated to ecstatic applause in Harlem for playfully singing a line from Al Green's hit, Let's Stay Together. That's a message the divided Republican party will take time to heed.
