Georgia Lt. Gov. Geoff Duncan, a Republican, told ABC News Live he's worried that President Donald Trump's baseless allegations of election fraud in the state "absolutely" might have depressed GOP turnout in the runoff races.

"Unfortunately, too many folks in our party over the last two months have been talking about misinformation, election fraud and creating a distraction," Duncan said.

"We've been outworked, out-focused, but my hope is that Kelly Loeffler's and David Purdue's hard work over the last two months is going to get them across the finish line and help us kind of regroup as a party here in this state, and also as a country, and be able to roll back out and get the White House in 2024," he added.

ABC News Chief Congressional Correspondent Mary Bruce stressed the significance of Tuesday's runoffs, not only because they will determine control of the Senate but because they leave President-elect Joe Biden's agenda hanging in the balance.

"It's not just how much he can get done but also the expediency with which he might be able to get things done," Bruce said, outlining big promises in Biden's agenda, from health care to climate change.

Biden has noted in recent days, while stumping for Democratic candidates, that if Democrats are able to win both seats, the $2,000 stimulus checks Democrats have been pushing for could happen immediately. Also, the approval of additional aid to state and local governments and resources to distribute the coronavirus vaccine in a more timely fashion could come quickly.

"Not to say that Joe Biden's agenda would hit a complete brick wall if Republicans continue to maintain control in the Senate because, of course, Joe Biden prides himself on having a great working and personal relationship with Republican leader Mitch McConnell, but it certainly would make Joe Biden's agenda and his political ambitions here much, much, much easier," Bruce said.

Bruce also noted how the expected efforts by Republicans to object to the certification of the Electoral College results on Wednesday could give the public a sense of the "uphill battle" Biden may face if the GOP does maintain control of the Senate.

The turnout of Black voters in Georgia’s runoff Senate races rose a percentage point from what it was in November, according to ABC News’ preliminary exit poll -- potentially a positive signal for Democratic candidates Jon Ossoff and Raphael Warnock.

The African American turnout is "a very encouraging sign for Democrats. It shows that they’re getting their base out,” ABC News Political Director Rick Klein said on ABC News Live.

Preliminary exit poll reporting shows that Black voters account for 29% of the electorate in Tuesday's race, up from 28% in November.

The exit poll data indicates that 93% of Black voters turned out for both Ossoff and Warnock.

"[African Americans are] as reliable of a Democratic bloc as there is and so far the Democrats look like they did their job in getting them to the polls," Klein said.

More than 3 million voters in the Georgia runoff elections cast their ballots early -- 1,018,381 by mail and 2,074,994 early in-person -- according to Georgia Votes, already a record-setting figure for runoff elections.

The total early vote so far also includes 123,079 who did not participate in November's general election -- which is 35,000 more votes than the margin that separated Sen. David Perdue and Jon Ossoff the first time around, when the incumbent Republican edged out his challenger by just over 88,000 votes. Sen. Kelly Loeffler and Raphael Warnock were competing in a jungle primary in which the large field diluted their vote shares.

The secretary of state's office won't have Tuesday's in-person turnout numbers until at least 1 p.m. on Wednesday when counties are required to report how many ballots they received Tuesday in order to calculate the number of outstanding ballots. It may take days for the final results to become available depending on how close the races are.

Republicans are relying on high Election Day turnout, believing close to a million votes on Tuesday is likely their path to victory. At a rally in Dalton on Monday night, President Donald Trump signaled how many votes Republicans are eyeing: "I guess we have to get over a million votes tomorrow, right, Kelly? Over a million. All right. That's a lot of votes, Kelly, but we'll do it."

-ABC News' Quinn Scanlan, Kendall Karson and Meg Cunningham

President-elect Joe Biden said that he feels "optimistic" about Tuesday's pivotal runoff elections in Georgia during an interview on V103 with Kenny Burns, a local Atlanta radio host.

"I'm doing really well, feeling really optimistic about today," Biden told Burns.

Asked what specific policies he expects to come before the Senate this year that make it so critical for Democrats Jon Ossoff and Rev. Raphael Warnock to win, Biden cited both the need to get $2,000 payments to struggling Americans and harshly criticized the federal government’s vaccine distribution plan at length, saying Congress needs to be able to provide support to get the vaccine out to all Americans.

"Right now, for example in Georgia, you have only about 75,000 people who have gotten the vaccination, yet you got about a half a million doses of that vaccine in the state. There's no planning. The federal government has done virtually no planning. It's one thing to get a vaccination -- to get to get the actual vial -- sent to you in a frozen pack. It's another thing to get it into a needle and the vaccination into somebody’s arm," Biden said.

"So I'm gonna need [Congress'] help in making sure that we establish thousands of federally-run and federally-supported community vaccination centers of various sizes across the country. Located in high school gyms or NFL football stadiums," Biden said, adding that the vaccination project has to involve multiple levels of the government including FEMA and the under his administration vaccines will be free.

"The inability of the president and the Republican leadership, and Trump in particular, preventing that from being made available to the states is just -- it's just almost criminal in my view. And people are dying,” Biden later added.

The president-elect once again hammered Georgia’s two Republican senators and candidates, Kelly Loeffler and David Perdue, saying they’ve forgotten who they have been elected to represent.

"Look here's the thing that's happening. Because of the Republican senators of Georgia, their loyalty is to Trump, not to the people of Georgia. I mean, when I got sworn into the Senate I didn't swear allegiance to the president, whether it was a Democrat or Republican. I'm not going to have any senators swear allegiance to me. It's to the Constitution and to the state of Georgia, that's who you represent," Biden said.

-ABC News' John Verhovek, Beatrice Peterson and Molly Nagle