Bernie Sanders is on a roll.

The self-described Democratic socialist swept to a huge Nevada victory over the weekend and polls indicate he now has a shot at even winning South Carolina's primary this Saturday—a contest that once was seen as former Vice President Joe Biden’s firewall.

The latest RealClearPolitics average for the state reflects a very tight race between the two. Biden remains in the lead with 24.5 percent of the vote, but Sanders is nipping at his heels with 21.5 percent, as the former vice president’s support has declined in the state.

BIDEN VOWS RESURGENCE AFTER SANDERS' NEVADA WIN

If Sanders is able to secure yet another primary victory with South Carolina, it would mark at least a three-state sweep out of the 2020 gate heading into Super Tuesday. Such an accomplishment, boosted by an enthusiastic base that turns out to vote and donates in big numbers, could render him just what party elders and members of the Democratic establishment fear—unstoppable.

While Sanders clearly won New Hampshire and Nevada, the only state he hasn't outright won so far is Iowa, where he and former South Bend, Ind., Mayor Pete Buttigieg ended in a virtual tie. Sanders won the popular vote in the state, but the national delegate count still favors Buttigieg in that contest. The contest remains in dispute, with the party announcing last week they will recount the presidential preference cards for 23 caucus precincts.

But Sanders' huge win in the Nevada caucuses -- he crushed the field by double-digit margins -- only strengthened his status as the front-runner in the crowded Democratic primary field, with only the South Carolina contest left until Super Tuesday next week when a massive chunk of delegates will be awarded.

The prospect of Sanders leveraging that momentum to build a daunting delegate lead next Tuesday has set off alarm bells in the party, with critics warning that his nomination would pave the way for President Trump’s re-election and potentially hurt Democrat’s chances of maintaining the majority in the House or taking the majority in the Senate.

SANDERS' WIN IN NEVADA REINFORCES FRONT-RUNNER STATUS, DRAWS ATTACKS FROM RIVALS

Last week, former Senate Majority Leader Harry Reid, D-Nev., appeared to nudge the center-left presidential candidates to eventually coalesce around one candidate who can win enough delegates to secure the nomination.

“A lot of this will work its way out,” he told The Washington Post. “A lot of people in the race still, but they’ll be dropping off quick because the money is running out. So I think you’re going to have the field winnowing pretty quickly.”

He added: “And you have most of the people who are not Bernie Sanders, are people who are moderates, and maybe they’ll work something out to get together and try to find that one person who can come up with the number of delegates. Maybe that’s one way to do it.”

But right now, the non-Sanders candidates are showing no inclination to make way for a consensus pick -- while still warning about the threat that Sanders will win if the field remains this large.

Former New York City Mayor Mike Bloomberg’s campaign manager Kevin Sheekey argued after Nevada that the results “reinforce the reality that this fragmented field is putting Bernie Sanders on pace to amass an insurmountable delegate lead.”

“This is a candidate who just declared war on the so-called 'Democratic Establishment.' We are going to need Independents AND Republicans to defeat Trump – attacking your own party is no way to get started,” Sheekey argued. “As Mike says, if we choose a candidate who appeals to a small base – like Senator Sanders – it will be a fatal error.”

Sheekey’s comments come after the campaign, ahead of last week’s debate, warned in an internal memo that Sanders would be nearly unstoppable unless other moderate candidates drop out before Super Tuesday.

Sanders made clear at last week's debate that he thinks the candidate with the most delegates—not necessarily the majority of delegates—at the end of the primary calendar should win the nomination. The other candidates on stage did not agree with that assertion -- seemingly entertaining the scenario of a contested convention where "superdelegate" party insiders could play a role.

After Nevada, Sanders' rivals cranked up their attacks. Buttigieg slammed his policies and said that he “believes in an inflexible, ideological revolution that leaves out most Democrats, not to mention, most Americans.”

Biden, who finished in second-place in Nevada, made an appeal to party loyalists.

“I’m a Democrat…and I’m proud of it,” Biden said, while taking a shot at Sanders.

“I was proud to run with Barack Obama,” Biden continued. “I’m proud to still be his friend and, I tell you what, I promise you I wasn’t talking about running a Democratic primary against him in 2012.”

Biden’s comment was an apparent swipe at Sanders, after reports surfaced last week that Sanders considered mounting a primary bid against Obama in 2012. Reid reportedly intervened to stop him.

But despite his lackluster performance early in the nominating calendar, Biden’s Nevada second-place finish gave him some much-needed momentum heading into South Carolina. Biden suffered disappointing fourth- and fifth-place finishes in the overwhelmingly white Iowa caucuses and New Hampshire primary, but Nevada’s more diverse electorate seemingly put Biden back on track.

“You all did it for me now, now we go to South Carolina and I’m going to take this back!” Biden said.

Fox News’ Paul Steinhauser contributed to this report.