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Republicans retained key Senate seats Tuesday in critical states -- setting up multiple roadblocks to Democrats' path to flip the Senate and dashing any hopes for a blue wave. 

GOP senators swatted down well-funded challenges in TexasIowa, South Carolina, Kansas and Montana, Fox News projected. And in the latest news Wednesday, GOP Sen. Susan Collins, a prime target for Democrats, declared victory in Maine shortly after 1 p.m. ET as her challenger Sara Gideon publically conceded that she "came up short."

"I feel that this is an affirmation of the work that I'm doing in Washington to fight hard every day for the people of Maine," Collins, a moderate, told cheering supporters Wednesday afternoon. 

Sen. Susan Collins, R-Maine, addresses supporters just after midnight on Wednesday, Nov. 4, 2020, in Bangor, Maine. (AP Photo/Robert F. Bukaty)

Sen. Susan Collins, R-Maine, addresses supporters just after midnight on Wednesday, Nov. 4, 2020, in Bangor, Maine. (AP Photo/Robert F. Bukaty)

With each win in these battlegrounds, Senate Majority Leader Mitch McConnell, R-Ky., is one step closer to holding the GOP majority -- a feat that seemed somewhat impossible with all the money and organizing effort liberals had put into flipping the Senate and election forecasters projecting the opposite. 

Speaking to reporters shortly after 11 a.m. ET Wednesday, McConnell said it was too early to tell whether Republicans had held the majority, given the number of outstanding races, but he projected favorable outcomes for the GOP in Maine and North Carolina. 

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"I don't know whether I'm going to be the majority leader or minority leader ... I've been both. The majority is better," McConnell quipped.

Republican Senate candidate Sen. Joni Ernst speaks to supporters at an election night rally, Tuesday, Nov. 3, 2020, in Des Moines, Iowa. (AP Photo/Charlie Neibergall)

Republican Senate candidate Sen. Joni Ernst speaks to supporters at an election night rally, Tuesday, Nov. 3, 2020, in Des Moines, Iowa. (AP Photo/Charlie Neibergall)

In one major victory, Sen. Lindsey Graham, R-S.C., fended off a serious scare from Democrat Jaime Harrison, who raised a record-breaking $107.6 million to challenge the powerful Judiciary Committee chairman. During his victory speech, Graham took aim at all the liberal donors who were banking on a GOP defeat.

"To all the pollsters out there, you have no idea what you are doing. And to all the liberals in California in New York, you wasted a lot of money," Graham said. “This is the worst return on investment in the history of American politics.”

Republicans were fighting to hold a slim 53-47 majority in the Senate. As of Wednesday morning, Democrats had only picked up a net gain of one seat, after winning Colorado and Arizona, but losing Alabama.

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Competitive races have yet to be called in Alaska, North Carolina, Michigan and two seats in Georgia that may not be decided until after the new Congress is sworn in next year.

Republican candidate for Senate Sen. Kelly Loeffler greets supporters as she walks on stage at an election night watch party in Atlanta, Tuesday, Nov. 3, 2020. Loeffler will be in a run off against Democratic candidate Raphael Warnock for the U.S. Senate seat. (AP Photo/Tami Chappell)

Republican candidate for Senate Sen. Kelly Loeffler greets supporters as she walks on stage at an election night watch party in Atlanta, Tuesday, Nov. 3, 2020. Loeffler will be in a run off against Democratic candidate Raphael Warnock for the U.S. Senate seat. (AP Photo/Tami Chappell)

At least one of the Georgia races was headed to a run-off in January between Sen. Kelly Loeffler, R-Ga., and Democrat Raphael Warnock, pastor at Ebenezer Baptist Church.

And Sen. David Perdue, R-Ga., was beating Democrat Jon Ossoff with 94 percent of the vote counted. If Perdue secures more than 50 percent of the final vote, he'll avoid a run-off election in January and return to the Senate for another six years. 

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Sen. Thom Tillis, R-N.C., had a slight edge over Cal Cunningham with 93% of the results in, but McConnell said it's too early to announce a win -- despite Tillis' earlier statements of victory.

Sen. Gary Peters, D-Mich., speaks at a campaign event before Democratic vice presidential candidate Sen. Kamala Harris, D-Calif., Tuesday, Tuesday, Nov. 3, 2020, in Southfield, Mich. (AP Photo/Carlos Osorio)

Sen. Gary Peters, D-Mich., speaks at a campaign event before Democratic vice presidential candidate Sen. Kamala Harris, D-Calif., Tuesday, Tuesday, Nov. 3, 2020, in Southfield, Mich. (AP Photo/Carlos Osorio)

Republicans could still pick up a seat in Michigan where incumbent Democratic Sen. Gary Peters is running neck-and-neck with GOP businessman John James as of 1 p.m. Wednesday. 

And GOP Sen. Dan Sullivan was comfortably ahead of Al Gross in Alaska, but with less than half the vote counted it was too early to declare a winner. 

Heading into Election night, Republicans were on defense with 12 GOP senators in competitive races, compared to only two Democrats in jeopardy.

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McConnell had previously pegged the odds of retaining control at 50-50. On Wednesday he said Republicans still need to do better in the suburbs, with women and with college-educated voters, but overall he seemed to think Republicans beat the odds.

"We had overall, I think, a better election than most people thought we were going to have across the country," McConnell said. "But, yeah, we have improvement we need to make."