The presidential campaign for candidate Joe Biden received another body blow on Thursday in the form of a damaging poll from the key primary state of South Carolina.

The former front-runner saw a lead as big as 20 points in the Winthrop University polling from September, but that has dwindled down to a mere 5-point lead.

The latest iteration of the Winthrop University polling shows Biden with only 24 percent support in South Carolina, with socialist firebrand Sen. Bernie Sanders (I-Vt.) increasing to 19 percent support.

Sanders improved by 8 percentage points from September in the same poll.

Biden has performed poorly in the first two state electoral contests of the Democratic primary, and this latest poll indicates his momentum is eroding. One advantage he has in South Carolina is his outsized support among African-Americans, who constitute a major part of Democratic voters in the state.

The surge in support for Sanders has left many of the centrist establishment Democrats sounding the alarm. MSNBC's Chris Matthews warned that the revolutionary strain of socialism had been tried in other countries and failed.

New York billionaire Mike Bloomberg entered the primary race and immediately attacked Sanders' socialism in the fiery Democratic debate on Wednesday.

The South Carolina primary election will be conducted on February 29.

Here's the latest on the Biden implosion: