Democratic U.S. Senate candidate Mark Kelly speaks to supporters during the Election Night event at Hotel Congress on November 3, 2020 in Tucson, Arizona.
CNN  — 

Sen. Mark Kelly raised nearly $9 million in the final three months of 2021, a figure that surpasses what he raised in the previous three months and positions the Arizona Democrat to be one of the best funded candidates in the 2022 midterms.

Kelly is seen as one of the most vulnerable Democrats in the United States Senate. Although he defeated former Republican Sen. Martha McSally in 2020 and President Joe Biden became the first Democratic presidential nominee to win Arizona since 1996, Republicans are buoyant that voters have soured on Democratic control and will punish the party at the ballot box in 2022.

But Kelly’s significant fundraising ability could be a bright spot for Democrats in an otherwise challenging year. The Kelly campaign is set to report that they entered the year with over $18.5 million in the bank and in the fourth quarter, according to the campaign, more than 125,000 contributors made 250,000 donations with an average contribution of $34.

“Just as Mark has refused to slow down as he delivers for Arizonans, neither have the grassroots donors who continue to fuel this campaign,” said Emma Brown, Kelly’s campaign manager. “Thanks to their strong support we’re moving full speed ahead into 2022, ready to re-elect Mark to the Senate.”

Kelly has long been a strong fundraiser. The retired astronaut, who is the husband of former Rep. Gabby Giffords, raised nearly $100 million in his 2020 campaign to defeat McSally, who had been appointed to the seat long held by the late Sen. John McCain. But Kelly’s fundraising this cycle is so far outpacing his earlier bid: The senator raised about $20 million in 2019 ahead of the 2020 election. Last year, he has raised $27.5 million, the campaign said.

Democratic fears about Republicans seizing power in 2022 were ratcheted up in 2021 when Republicans swept the statewide elections in Virginia, a state Biden carried by 10 percentage points, and nearly ousted New Jersey Gov. Phil Murphy in a state Biden won by 16 percentage points a year earlier.

Sensing a chance to oust an incumbent Democrat, a handful of Republicans have lined up to take on Kelly, including Arizona Attorney General Mark Brnovich; Blake Masters, the president of the Thiel Foundation; and businessman Jim Lamon.

None of these Republicans, however, have been able to keep up with Kelly’s fundraising.

Lamon is primarily self-funding his campaign, while Brnovich announced this week that his campaign raised $800,000 in the fourth quarter of 2021, after raising $563,000 in the third quarter.

Masters, by contrast, announced earlier this week that he raised $1.38 million in the final three months of 2021, an increase from the $1.01 million he raised in the third quarter of 2021. Peter Thiel, a tech billionaire who has long worked with Masters, is also expected to spend $10 million on a Super PAC supporting the Republican candidate.

Because the Senate is currently evenly split, every competitive race in 2022 will be a high stakes affair, with both parties desperate to control the legislative body in 2023 and ahead of the 2024 presidential election.

To date, Democrats in competitive races across the country have maintained strong fundraising advantages over their potential Republican opponents, a silver lining for a party that knows the party in control of the White House often loses legislative seats in the subsequent midterms.

Georgia Sen. Raphael Warnock, another vulnerable Democratic incumbent, raised $9.5 million in the third quarter of 2021. Republican Herschel Walker, Warnock’s likely Republican opponent in 2022 and a former star University of Georgia running back, raised $3.7 million in the same three months. Neither Warnock not Walker have put out their fourth quarter fundraising numbers.

Senate candidates who won’t have the power of incumbency have also announced sizable hauls from 2021.

Rep. Tim Ryan, an Ohio Democrat who is running for the state’s open Senate seat, announced on