NBC News predicts that Democrat Raphael Warnock will be re-elected to the U.S. Senate, which is crucial for President Joe Biden.
His expected victory gave Democrats a supermajority after ending two years with a 50-50 margin in the Senate, with Vice President Kamala Harris casting the tie-breaking vote.
Mr Warnock defeated Republican opponent Herschel Walker – a former NFL star – during the Georgia campaign.
The runoff was triggered after neither candidate won an outright majority in last month’s midterm elections.
Mr Warnock told supporters in his victory speech: “After a tough campaign – or should I say campaign – I am honored to be able to say four of the most powerful words democracy has ever seen: The people have spoken .”
Mr. Biden called him to congratulate him.
He tweeted: “Georgia voters tonight stand for our democracy, reject Ultra MAGAism, and most importantly: send a good guy back to the Senate. 6 years to go.”
Mr Walker, a 1980s NFL legend, has been unable to overcome a string of damaging allegations, including claims he paid for the abortions of two ex-girlfriends.
As a multimillionaire businessman, he has exaggerated his philanthropic activities and business achievements, including claims that his companies employ hundreds of people and generate tens of millions of dollars in annual sales, although records show he had eight employees, an average Salaries are around $1.5m (£1.2m) a year.
He has stated that he has worked as a law enforcement officer and is a college (university) graduate, although he has done neither.
His Senate bid was endorsed by former President Donald Trump.
Another sign that America is shedding Donald Trump as a political force
After following Herschel Walker on the Georgia campaign trail, it’s hard to believe this game ever made it to the final.
The former NFL star has struggled to deliver a coherent message, in stark contrast to the abysmal speeches of his counterpart, the Reverend Raphael Warnock, a professional preacher who commanded audiences .
Walker was handpicked as a candidate by former President Donald Trump, but his reputation was shattered on the campaign trail.
He ran on a pledge against abortion, but two women claimed he paid for their abortions after they became pregnant (a claim he denies). He also condemned absentee fathers, especially in black families, but later admitted he had a son he never saw.
But his defeat matters not just to Democrats, because of the rejection of his personal integrity — or lack thereof — and the values he espouses to make America great again.
It also means — for the first time in Joe Biden’s presidency — his party has an absolute majority in the Senate.
The new 51-49 split means Democrats can speed up the Senate Judiciary Nominating and Control Committee. But it also avoids a situation where one senator — Joe Manchin or Kirsten Sinema in the past two years — could use their swing vote as a weapon.
Perhaps most importantly, though, it was yet another sign that America was moving away from Trump as a political force.
On the campaign trail, Mr. Warnock, the state’s first black senator, touted his gains in the Senate, touting a provision he sponsored to cap the cost of insulin for low-income patients, as well as deals on infrastructure and maternal health care.
Senate Majority Leader Chuck Schumer said Mr Warnock’s victory was “against MAGA’s Republican extremist policies”.
The final weeks of the election season have become increasingly painful. Mr Walker called Mr Warnock, the senior pastor of Ebenezer Baptist Church in Atlanta, Georgia’s capital, a “hypocrite” who was at the beck and call of President Joe Biden.
Despite being a Democrat, Mr. Warnock has sought to distance himself from Mr. Biden, who is lagging behind amid persistently high U.S. inflation.
Democrats’ new supermajority in the Senate doesn’t spell the end of a divided government, as Republicans narrowly flipped control of the House in recent midterm elections, but it does mean they will now control powerful committees.