Democrats flipped a US Senate seat in Colorado November 4 in their bid to regain control of the upper chamber of Congress, but Republicans countered by ousting a vulnerable Democrat in Alabama, networks projected.
With control of the Senate up for grabs, Democrats put their stamp once again on the House of Representatives, securing another two years as the party in power with Speaker Nancy Pelosi -- President Donald Trump's chief nemesis in Washington -- likely to preside over her flock again.
"I'm very, very proud of the fact that tonight -- relatively early -- we are able to say we have held the House," Pelosi said.
In the more closely-watched Senate showdown, Democrats drew first blood when Colorado's former governor John Hickenlooper, a 68-year-old businessman and geologist, handily defeated one-term Senator Cory Gardner to pick up a seat.
"Thank you, Colorado! Serving you is the honor of my life, and I can't wait to be your Senator," Hickenlooper said on Twitter.
Republicans are scrambling to preserve their 53-47 Senate majority, with polls showing several races tilting towards Democrats. Election forecaster FiveThirtyEight.com give Democrats a three in four chance of winning Senate control.
Democratic nominee Joe Biden's party would need to gain four seats to seize the chamber -- or three seats if Biden wins the White House, as a US vice president breaks a tie in the Senate in the event of a 50-50 vote.
Republicans got a defensive boost though when retired American football coach Tommy Tuberville, 66, handily defeated Senator Doug Jones in a race that was widely expected to result in a Republican pick-up.
Jones had faced steep reelection odds in a ruby-red southern state after winning in a 2017 special election upset against Roy Moore, a Republican who faced sexual misconduct allegations.
And Republicans received more good news Tuesday when political veteran Lindsey Graham who oversaw the controversial process of confirming a Supreme Court justice weeks before the presidential vote, won reelection in South Carolina.
Graham, a Trump ally, survived a spirited challenge by Democrat Jaime Harrison, according to Fox News and The New York Times which called the race with nearly half the precincts reporting.
The African-American Harrison had been running neck-and-neck with the 65-year-old Republican incumbent just weeks before the election in a conservative Southern bastion, and raised an all-time record in campaign donations as Democrats saw the seat as a potential pick-up.
"We didn't get the result at the ballot box that we wanted, but we showed courage and determination," Harrison said in a statement.
Meanwhile the Senate's top Republican, Majority Leader Mitch McConnell of Kentucky, won reelection against former fighter pilot Amy McGrath, ensuring that the most powerful Republican in Congress will remain in the chamber for another six years.
Controlling the Senate is vital as the party in power controls which bills reach the floor and which of the president's nominees receive confirmation votes.