Democratic Senator Raphael Warnock has defeated Republican challenger Herschel Walker in Georgia's runoff election, to secure the Democrats an outright majority in the Senate for the rest of US President Joe Biden's term.
With Senator Warnock's second runoff victory in as many years, Democrats will have a 51-49 Senate majority.
There will be divided government, however, with Republicans having narrowly flipped control in the House of Representatives.
Earlier polling showed Mr Warnock slightly ahead of Trump-endorsed former NFL player Mr Walker, but the difference had been close to or within the margin of error.
More than 1.85 million voters in Georgia cast their ballots during an early voting period, which closed on Friday, according to the Secretary of State's office.
Elections officials reported few problems processing early votes and tabulating ballots cast on Tuesday, but there were some delays.
In south Georgia's Lowndes County, two poll workers were in a car crash on the way to the county elections office with the memory cards from one precinct's polling machines.
A Lowndes official said a member of the local elections board went to the crash site to retrieve the memory cards so tabulations could continue.
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Political analysts say those early votes traditionally lean more towards the Democrats, with Republicans tending to vote in bigger numbers on election day.
The Democrats secured effective control of the Senate in the general election, which was held on November 8, winning the minimum 50 seats.
Incumbent Nevada senator Catherine Cortez Masto won the Democrats' 50th Senate seat after several days of vote-counting last month, meaning the party narrowly maintained control of the chamber with the help of Vice-President Kamala Harris's tiebreaker vote.
Republican incumbent Brian Kemp was re-elected as Georgia's governor in November's midterm elections, and eight of Georgia's 14 seats in the House of Representatives were also won by Republicans, including controversial incumbent Marjorie Taylor Greene in the state's 14th district.
How the campaign played out
Mr Walker benefited during the campaign from nearly unmatched name recognition from his football career, yet was dogged by questions about his fitness for office and allegations of hypocrisy.
Mr Walker inflated his philanthropic activities and business achievements, including claiming that his company employed hundreds of people and grossed tens of millions of dollars in sales annually.
He suggested that he had worked as a law enforcement officer and graduated college, though he had done neither.
He was accused by two former girlfriends of encouraging and paying for their abortions, despite supporting an outright national ban on the procedure during the campaign. He denied both women's claims.
Mr Walker urged his supporters to "flood the polls" on election day.
"We've got to get in the game, get out to vote, and that's the way your voice is going to be heard, it's going to be heard if you get out and vote," he said.
Mr Walker sought to portray Mr Warnock as a yes-man for Mr Biden, accusing him of "being on his knees, begging" at the White House.
"My opponent is not a serious person," Mr Warnock said during the campaign.
"But the election is very serious. Don't get those two things confused."
Mr Warnock, the state's incumbent senator, promoted his accomplishments, touting a provision he sponsored to cap insulin costs for Medicare patients.
He hailed deals on infrastructure and maternal health care forged with Republican senators, mentioning those GOP colleagues more than he did Mr Biden or other Washington Democrats.
Mr Warnock declared at a rally on the eve of the runoff that he would "stand up for you for six more years".
He distanced himself from Mr Biden, whose approval ratings have lagged as inflation remains high.
He decided instead to campaign with former president Barack Obama in the days before the runoff election.
Mr Walker, meanwhile, avoided campaigning with Trump until the campaign's final day, when the pair conducted a conference call on Monday with supporters.
Mr Walker joins failed Senate nominees Dr Mehmet Oz of Pennsylvania, Blake Masters of Arizona, Adam Laxalt of Nevada and Don Bolduc of New Hampshire as Trump loyalists who ultimately lost races that Republicans once thought they could win.
