Joe Biden says Democrats could have 'great trouble' with Bernie Sanders at top of the ticket

Joe Biden joined ABC's "This Week" following a commanding win in South Carolina.

"Well I think he's gonna have -- he'll have great trouble bringing along other senators, keeping the House of Representatives, winning back the Senate and down-ballot initiatives. So I think -- I think it is a stark choice and it's not about whether or not we restore the soul of the Democratic Party. It's about restoring the soul and unite this country, the whole country," Biden told ABC News Chief Anchor George Stephanopoulos on Sunday. "And I think -- I think I can do that."

His interview came after a big win in the South Carolina primary -- the first state the former vice president has won in his three presidential campaigns.

Biden said he’s feeling good following his win in South Carolina, but with Super Tuesday rapidly approaching and former New York Mayor Michael Bloomberg's name soon to appear on ballots, questions remain about Biden's ability to translate this first win into further results -- especially given reports of lackluster organization on the ground.

The former vice president acknowledged on Sunday that changes to his campaign are needed and coming.

"This is a matter of addition, not subtraction," he said. "And so we're attracting more and more people, we're adding more competent people -- additional people -- are very competent. I feel good about the top part of my campaign, we've had some difficulties across the board and in terms of field organization. That's getting better."

"Now we're in a position where we're beginning to raise some real money and we feel good about where we're going -- but we always can improve. We always can improve. And I can improve as well," Biden added.

South Carolina has catapulted the former vice president into the second-place position in the delegate hunt, where he now trails Sanders by five delegates. It is an upswing for Biden's campaign following two disappointing finishes in Iowa and New Hampshire and coming in at a distant second place behind the Vermont senator in the Nevada caucuses.

The win also brought an influx of fundraising money to the campaign.

"This month we raised -- which for us is a lot of money -- I guess its about close to $18 million. We raised $5 million just from the win last night," Biden said.

One thing that has still not come in the 2020 race is an endorsement from the man he served with in the White House, former President Barack Obama. When asked on "This Week" if the lack of endorsement was hurting his campaign, Biden pushed back on the notion.

"No, It isn’t hurting me. I don't think it's time. He and I have talked about this in the very beginning--I have to earn this of my own," Biden told Stephanopoulos.

"The first thing everybody said when I announced, the opposition -- the Democratic opposition -- said 'Biden feels entitled because he's vice president.' Imagine, had president endorsed me, it would have been 'Biden’s entitled' because -- he thinks he's entitled because -- of the president’s endorsement. The president and I are close friends, and I have no doubt when I win this nomination he will be out there full bore for me.”

Biden's team has long argued that the former vice president would flourish in more diverse states that better reflect the U.S. population.

Asked by Stephanopoulos about his disadvantage in resources compared to Sanders, heading into Tuesday, Biden acknowledged that he has been outspent by the Vermont senator, but said his message and ability to win in states Democrats need to win back the U.S. Senate and hold their majority in the U.S. House will enable him to perform well.

"(Sanders) obviously has outspent me 10 to one or beyond that. But I think it's as much the message and what we stand for and what we're going to do. ... But we still have to come along and win the Senate, we have to win in North Carolina, we have to win in Georgia, we have to win in Texas, Florida, etcetera," Biden said.

Biden also slammed Sanders for his change in position on whether the candidate who has earned the most pledged delegates heading in the Democratic National Convention in July should automatically become the party’s presidential nominee.

"Don't you find, George, that there's not a lot of consistency coming out of some of these campaigns?" Sanders asked on "This Week" Sunday. "He wanted to make sure that you didn't enter with the most delegates and be the automatic nominee when he was running against Hillary (Clinton) and all of a sudden he's had an epiphany."

Asked where he believes he will do well on Tuesday, Biden pointed South.

"I think we can win most of the southern states -- we're in contention, including in Texas. It's been very hard to make up the ground in California, but I think we can make up a lot of ground in California in three days. And so I feel good about where it goes and Super Tuesday is not the end, it's only the beginning," Biden said. "We're about even on delegates right now, we've had more popular votes thus far than Sanders does. I feel good about going to places where I've always had significant support from the people that make up the democratic electorate."

Biden next embarks on a multi-state sprint across the country leading up to Super Tuesday, with campaign events in Alabama, Virginia, Texas and California.