With Ossoff's win, Democrats effectively control the legislative and executive branches -- the Senate will be split 50-50, with Vice President-elect Kamala Harris casting tie-breaking votes when needed.
Ossoff led Perdue by 24,859 votes -- 0.6 percent -- when the race was called, with 98 percent of precincts reporting.
Ossoff had declared victory in the Georgia Senate runoff race earlier Wednesday, as Perdue's campaign promised to "exhaust" all legal options to ensure only "legally cast" ballots were counted.
"This campaign has been about health and jobs and justice for the people of this state ... and they will be my guiding principles as I serve this state in the U.S. Senate," Ossoff said in a livestreamed address on Wednesday morning.
Meanwhile, Democrat Raphael Warnock is projected to defeat Sen. Kelly Loeffler, R-Ga., according to Fox News' Decision Desk.
Loeffler encouraged her supporters early Wednesday to "keep fighting," refusing to concede despite Warnock declaring victory.
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