Talk about finding mojo.

Four days removed from a winless record in the fight for the Democratic presidential nomination, former Vice President Joe Biden prevailed in a string of Southern states Tuesday. He added hundreds of delegates to a campaign train that launched out of South Carolina on Saturday and has been picking up steam ever since.

"We were told when you get to Super Tuesday, it may be over," Biden told supporters Tuesday night, his voice full of excitement. "Well, it may be over for the other guy."

The centrist's early victories in Virginia, North Carolina, Alabama and Tennessee — fueled by large majorities among African American voters — promised to put him in a strong position to fight Vermont Sen. Bernie Sanders for the right to take on President Donald Trump in November. His better-than-expected showing along I-35 — where he won Texas, Oklahoma and Minnesota — and in New England threatened to knock Sanders and the progressive wing of the Democratic Party on its heels.

"What we are watching is the voices of African American and other diverse communities being heard loudly around the nation," said Marcus Mason, a Biden donor and former senior director of government affairs for Amtrak. "South Carolina was not a firewall, but a foundation for what was to come."

On the other side, Sanders was suddenly looking at turned tables. Less than two weeks ago, he had won the popular vote in his third straight state to start the primaries and there was talk in both progressive and centrist circles that Super Tuesday could put him on a glide path to the nomination. Biden silenced that chatter.

"It’s very fluid, but Bernie Sanders is not going to be coronated tonight as his supporters had hoped," Melissa K. Miller, a political science professor at Bowling Green State University said Tuesday night. "It’s going to shape up to be a two-person race."

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In remarks to a boisterous crowd at his campaign headquarters in his home state of Vermont Tuesday night, Sanders said a recent winnowing of the Democratic field would benefit him by turning attention to elements of Biden's record that he portrayed as too conservative for the party's electorate.

"This will become a contrast in ideas," Sanders said.

His strongest states were in the West, where polls closed later, and the final delegate tallies could take days to come in. But some of his allies were quick to reframe what they had originally seen as a big night for him.

"OK Boomer pundits: take a deep breath!" New York Mayor Bill de Blasio, who has endorsed Sanders, wrote on Twitter. "The game has just begun. The 2 largest states in the nation haven’t spoken yet tonight. And many big states in weeks ahead. It’s a 2-person race, totally clear contrast. Debates loom large. And THAT is a very GOOD formula for @BernieSanders."

Those two biggest states, California and Texas, together account for more than 600 delegates to the Democratic convention this summer. Biden surged to a surprise win in Texas, NBC News projected, and by 3 a.m. ET Wednesday, with Sanders having won Vermont, Utah and Colorado, Biden's delegate lead over Sanders stood at 420 to 327, according to NBC's delegate tracker.

Sanders spokesman Michael Casca had argued that the motherlode states would alter the narrative of Super Tuesday by Wednesday morning.

"If you turn off your television at 10 p.m. tonight you will wake up tomorrow to a different race," he said.

Still, it was clear that most traditional Democrats had consolidated their support behind Biden, who was aided by the abrupt exits from the race of former South Bend, Indiana, Mayor Pete Buttigieg and Sen. Amy Klobuchar, D-Minn. Both of them dropped their bids and endorsed Biden in recent days, clearing the way for many of their supporters to switch to Biden.

Mason pointed to the "Clyburn effect" as the kindling that turned Biden's campaign around. With Biden heading into Saturday's South Carolina primary having failed to win a state, House Majority Whip Jim Clyburn, D-S.C., the highest-ranking African American in Congress, endorsed him.

"It began with the Clyburn effect," Mason said in a text message, "when one good man spoke up for another and the people listened and responded."

Clyburn told NBC's Lester Holt on Tuesday night that he sensed a change in Biden in recent days — that the former vice president was finally getting voters "to feel him" rather than just hearing him when he speaks.

Whether they heard him, felt him or just preferred him to the remaining candidates, they certainly had fewer choices. By Tuesday morning, the set of White House hopefuls in contention for the Democratic nomination had been reduced to Biden, Sanders, Massachusetts Sen. Elizabeth Warren, billionaire Michael Bloomberg and Rep. Tulsi Gabbard, D-Hawaii.

And Biden had picked up a lot of support from his former rivals.

"People are talking about a revolution," he said, referring to Sanders' call for a political revolution. "We've started a movement."

There was no doubt the race had moved in his direction Tuesday night.