According to Bloomberg, Alaska was called late because state law required local officials carefully examine each mail-in ballot before counting could officially begin on Tuesday.

Sullivan defeated Al Gross, an independent who was backed by national Democrats in their effort to flip the seat. Gross is a former orthopedic surgeon and commercial fisherman and is the son of former Alaska Attorney General Avrum Gross (D). According to The Hill, the loss marked another state where Democrats failed to unseat Republicans in seats seen as closely contested. Sens. Susan Collins (R-Maine), Joni Ernst (R-Iowa) and Thom Tillis (R-N.C.) all won reelection in states highly targeted by Democrats.

"I want to congratulate my fellow Marine, Senator Dan Sullivan on his victory. Alaskans know Dan as a man who always puts service before self and who has championed the unique needs of his state in Washington," National Republican Senatorial Committee Chairman Sen. Todd Young (R-Ind.) said in a statement. "The state will be well served with another six years of his representation."

Sullivan's win means that, as widely expected, majority control will depend on the winners of two January runoffs in Georgia.

If Democrats win both, the chamber will be tied 50-50, with Vice President-elect Kamala Harris casting the tie-breaking vote. But if they lose either one, Republicans will control the majority as President-elect Joe Biden takes office.

According to polls, Democrats face an uphill battle if they hope to reverse the results of initial vote in Georgia where the two Democratic candidates lagged their GOP challengers.