ATLANTA (NewsNation Now) — President-elect Joe Biden visited Georgia Tuesday to campaign for two Democratic candidates in the Jan. 5 runoff elections that will determine which party controls the Senate.

Biden traveled to the Peach State a day after the Electoral College confirmed his presidential victory. President Donald Trump still has not conceded, which added importance to the state-by-state elector voting formality this year.

Biden campaigned Tuesday on behalf of Democratic Senate candidates Jon Ossoff and Raphael Warnock, who are facing Republican Senators David Perdue and Kelly Loeffler in the runoff races next month.

The president-elect warned that Republican victories would leave him to face the kind of GOP obstruction that hampered former President Barack Obama for most of his two terms.

“I need two senators from this state who want to get something done,” Biden said at the drive-in rally near downtown Atlanta, criticizing Perdue and Loeffler for not supporting a sweeping new economic aid package as the coronavirus pandemic surges.

“Are you ready to vote for two United States senators who know how to say the word ‘yes’ and not just ‘no’?” Biden said.

Biden’s narrow win in the Southern state in November’s presidential election completed its transformation from Republican stronghold to one of the country’s most competitive political battlegrounds.

If the Republicans win either contest, they would maintain power in the Senate, allowing them to thwart many of Biden’s ambitious legislative goals on issues such as the coronavirus, the economy and climate change. A Democratic sweep would give the party control of the White House and Congress, where it also has a majority in the U.S. House of Representatives.

Biden’s trip to Atlanta comes nine days after President Donald Trump traveled to Georgia in support of Perdue and Loeffler. The president-elect’s visit also coincides with early in-person voting, which began on Monday as hundreds of Georgians braved rainy weather to stand in line.

As in November, many voters are expected to cast ballots by mail amid the ongoing coronavirus pandemic. Thus far, more than 1.2 million residents have requested absentee ballots, and more than 260,000 have already sent them in, according to the U.S. Elections Project at the University of Florida.

Perdue finished ahead of Ossoff in the Nov. 3 election but just shy of the 50% required to avoid a runoff under state law. A third-party candidate received about 2% of the vote.

The other race had a large field of candidates in November due to its status as a special election because Loeffler was appointed to her seat to fill a vacancy. Warnock and Loeffler finished in the top two positions, each well short of 50%.

The Associated Press and Reuters contributed to this report. All reporting by Reuter’s Joseph Ax and Bill Barrow and Aamer Madhani/AP.