Senate Republicans defied the odds Tuesday and beat back Democrats’ all-out push to win the Senate majority.

The victory is a huge win for Senate Majority Leader Mitch McConnell Addison (Mitch) Mitchell McConnellPelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Senate GOP aims to confirm Trump court pick by Oct. 29: report Trump argues full Supreme Court needed to settle potential election disputes MORE (R-Ky.), who took a hands-on role in crafting the defense of 24 Senate seats in what was projected to be a tough cycle for GOP incumbents.

But many of the Senate GOP incumbents that Democrats hoped to unseat stayed afloat as Donald Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE dramatically outperformed expectations to clinch the presidency.

Democrats had picked up only one Republican-held seat as of 3 a.m. Wednesday, knocking off Sen. Mark Kirk Mark Steven KirkLiberal veterans group urges Biden to name Duckworth VP On the Trail: Senate GOP hopefuls tie themselves to Trump Biden campaign releases video to explain 'what really happened in Ukraine' MORE in Illinois. It was a massive disappointment compared to their high hopes only a few weeks before Election Day, when they predicted a gain of as many as seven seats.

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The result was a dramatic turnabout from earlier in the day, when Senate Republican strategists gave themselves slim chances of keeping the majority and blamed Trump’s undisciplined campaign for stepping on their message.

Democrats’ dreams of winning back the majority ultimately crumbled around 11 p.m., when media outlets called the Wisconsin race for Sen. Ron Johnson Ronald (Ron) Harold Johnson CIA found Putin 'probably directing' campaign against Biden: report This week: Supreme Court fight over Ginsburg's seat upends Congress's agenda GOP set to release controversial Biden report MORE (R), a seat that Democrats had for months counted as one of their best pick-up opportunities.

In addition to Johnson, GOP incumbent Sens. Marco Rubio Marco Antonio RubioOvernight Defense: Pentagon redirects pandemic funding to defense contractors | US planning for full Afghanistan withdrawal by May | Anti-Trump GOP group puts ads in military papers Democrats step up hardball tactics as Supreme Court fight heats up Press: Notorious RBG vs Notorious GOP MORE (Fla.), Roy Blunt Roy Dean BluntSocial media platforms put muscle into National Voter Registration Day Senate GOP faces pivotal moment on pick for Supreme Court This week: Supreme Court fight over Ginsburg's seat upends Congress's agenda MORE (Mo.), Richard Burr Richard Mauze BurrRep. Mark Walker says he's been contacted about Liberty University vacancy Overnight Defense: Trump rejects major cut to military health care | Senate report says Trump campaign's Russia contacts posed 'grave' threat Senate report describes closer ties between 2016 Trump campaign, Russia MORE (N.C.), John McCain John Sidney McCainCindy McCain endorses Biden: He's only candidate 'who stands up for our values' Biden says Cindy McCain will endorse him Biden's six best bets in 2016 Trump states MORE (Ariz.), Pat Toomey (Pa.), Rob Portman Robert (Rob) Jones PortmanMcConnell locks down key GOP votes in Supreme Court fight Romney undecided on authorizing subpoenas for GOP Obama-era probes Congress needs to prioritize government digital service delivery MORE (Ohio), all won Tuesday, along with Rep. Todd Young Todd Christopher YoungSenate GOP eyes early exit Why the US should rely more on strategy, not sanctions Davis: The Hall of Shame for GOP senators who remain silent on Donald Trump MORE in Indiana.

"Republicans won because we had better candidates, ran better campaigns, invested early and starting on day one, made every preparation to run in an uncertain and volatile political environment," said National Republican Senatorial Committee (NRSC) Chairman Roger Wicker Roger Frederick WickerBottom line Hillicon Valley: DOJ indicts Chinese, Malaysian hackers accused of targeting over 100 organizations | GOP senators raise concerns over Oracle-TikTok deal | QAnon awareness jumps in new poll Shakespeare Theatre Company goes virtual for 'Will on the Hill...or Won't They?' MORE (Miss.).

The race in New Hampshire was too close to call at 3:15 a.m. with Sen. Kelly Ayotte Kelly Ann AyotteBottom line Bottom line Bottom Line MORE (R-N.H.) ahead of Gov. Maggie Hassan (D) by about 600 votes. Neither candidate appeared ready to concede early Wednesday morning.

Republican Sen. Chuck Grassley Charles (Chuck) Ernest GrassleyCollins says she will vote 'no' on Supreme Court nominee before election The Hill's Morning Report - Sponsored by Facebook - Trump, GOP allies prepare for SCOTUS nomination this week Gardner signals support for taking up Supreme Court nominee this year MORE, whom Democrats thought earlier in the election cycle might be vulnerable, won in Iowa. Democrats had hoped to make that race about Grassley’s role as Judiciary Committee chairman in the stalemate over the Supreme Court.

Democrats counterpunched with a victory in Illinois, where Rep. Tammy Duckworth knocked off incumbent Sen. Mark Kirk (R) to flip one seat.

Former Attorney General Catherine Cortez Masto is projected to win in Nevada, according to the AP. That win keeps outgoing Senate Minority Leader Harry Reid Harry Mason ReidThe Supreme Court vacancy — yet another congressional food fight Trump seeks to turn around campaign with Supreme Court fight On The Trail: Battle over Ginsburg replacement threatens to break Senate MORE's seat in the "D" column and gave Democrats a small consolation prize.

They also held the Colorado seat, where Sen. Michael Bennet Michael Farrand BennetOVERNIGHT ENERGY: House Democrats tee up vote on climate-focused energy bill next week | EPA reappoints controversial leader to air quality advisory committee | Coronavirus creates delay in Pentagon research for alternative to 'forever chemicals' Senate Democrats demand White House fire controversial head of public lands agency Next crisis, keep people working and give them raises MORE won reelection.

Democrats entered the day assuming they would need to pick up four seats to win back the majority because Hillary Clinton Hillary Diane Rodham ClintonButtigieg stands in as Pence for Harris's debate practice Senate GOP sees early Supreme Court vote as political booster shot Poll: 51 percent of voters want to abolish the electoral college MORE was considered such a prohibitive favorite to win the White House. By midnight, the landscape had changed.

The results are an embarrassing setback for retiring Senate Democratic Leader Harry Reid (Nev.) and his top deputy, New York Sen. Chuck Schumer Chuck SchumerSenate Democrats introduce legislation to probe politicization of pandemic response Schumer interrupted during live briefing by heckler: 'Stop lying to the people' Jacobin editor: Primarying Schumer would force him to fight Trump's SCOTUS nominee MORE (D), who thought he was poised to become the next Senate majority leader when he won reelection Tuesday night.

Republicans were helped by surprising turnout for Trump, and a massive infusion of cash into the Senate races from donors who were disillusioned with the top of the ticket.

McConnell will get credit for recruiting rising-star Rubio to run for reelection in Florida and building a network of donors who contributed $165 million to outside groups involved in Senate races. It also appears their warnings about the consequences of a Democratic majority in the Senate helped them hold their majority.

GOP incumbent Sens. Lisa Murkowsi (Alaska), Mike Crapo Michael (Mike) Dean CrapoBottom line Davis: The Hall of Shame for GOP senators who remain silent on Donald Trump Top GOP senator urges agencies to protect renters, banks amid coronavirus aid negotiations MORE (Idaho), Mike Lee Michael (Mike) Shumway LeeMcConnell shores up GOP support for coronavirus package McConnell tries to unify GOP Davis: The Hall of Shame for GOP senators who remain silent on Donald Trump MORE, (Utah), Johnny Isakson Johnny IsaksonLoeffler paints herself as 'more conservative than Attila the Hun' in new campaign ad Georgia GOP Senate candidates cite abortion in pushing Ginsburg replacement Loeffler: Trump 'has every right' to fill Ginsburg vacancy before election MORE (Ga.), John Boozman John Nichols BoozmanCOVID-19 relief talks look dead until September Senate GOP hedges on attending Trump's convention amid coronavirus uptick The Hill's Coronavirus Report: San Francisco Gay Men's Chorus Artistic Director Tim Seelig says choirs are dangerous; Pence says, 'We have saved lives' MORE (Ark.), John Thune John Randolph ThuneSenate GOP sees early Supreme Court vote as political booster shot Romney backs pre-election Supreme Court vote, paving way for McConnell, Trump Senate GOP faces pivotal moment on pick for Supreme Court MORE (S.D.), John Hoeven John Henry HoevenDavis: The Hall of Shame for GOP senators who remain silent on Donald Trump Bottom line Bipartisan senators seek funding for pork producers forced to euthanize livestock MORE (N.D.), Jerry Moran Gerald (Jerry) MoranLobbying world This World Suicide Prevention Day, let's recommit to protecting the lives of our veterans Hillicon Valley: Zuckerberg acknowledges failure to take down Kenosha military group despite warnings | Election officials push back against concerns over mail-in voting, drop boxes MORE (Kan.), James Lankford (Okla.), Rand Paul Randal (Rand) Howard PaulSecond GOP senator to quarantine after exposure to coronavirus GOP senator to quarantine after coronavirus exposure The Hill's Morning Report - Sponsored by National Industries for the Blind - Trump seeks to flip 'Rage' narrative; Dems block COVID-19 bill MORE (Ky.), Richard Shelby (Ala.) and Tim Scott Timothy (Tim) Eugene ScottAuthor Ryan Girdusky: RNC worked best when highlighting 'regular people' as opposed to 'standard Republicans' Now is the time to renew our focus on students and their futures GOP lobbyists pleasantly surprised by Republican convention MORE (S.C.) were projected to win their Senate races.

Notching victories on the Democratic side were Sens. Ron Wyden Ronald (Ron) Lee WydenGOP set to release controversial Biden report Democrats fear Russia interference could spoil bid to retake Senate GOP senator blocks Schumer resolution aimed at Biden probe as tensions run high MORE(Ore.), Patty Murray Patricia (Patty) Lynn MurraySenate Democrats introduce legislation to probe politicization of pandemic response Trump health officials grilled over reports of politics in COVID-19 response CDC director pushes back on Caputo claim of 'resistance unit' at agency MORE (Wash.), Brian Schatz (Hawaii), Patrick Leahy Patrick Joseph LeahyBattle over timing complicates Democratic shutdown strategy Hillicon Valley: Russia 'amplifying' concerns around mail-in voting to undermine election | Facebook and Twitter take steps to limit Trump remarks on voting | Facebook to block political ads ahead of election Top Democrats press Trump to sanction Russian individuals over 2020 election interference efforts MORE (Vt.) and Richard Blumenthal (Conn.), as well as Rep. Chris Van Hollen (Md.) and California Attorney General Kamala Harris.

Altogether, Republicans, including candidates, party committees and allied super PACs, spent $422 million on Senate races this cycle, according to a tally provided by the Democratic Senatorial Campaign Committee (DSCC).

Democrats spent a total of $383 million, according to the same tally.

A Senate Republican strategist who tracks media buys provided different numbers, but they still showed the GOP with a spending advantage.

Spending by Republican candidates, party committees and super PACs totaled $473.3 million, according to that source. Democratic spending across those same categories totaled $439.5 million.

A Republican source familiar with internal spending records said the Senate Leadership Fund, a group linked to McConnell and two affiliated groups, One Nation and Granite State Solutions, raised and spent $165 million.

McConnell also raised $5 million for the National Republican Senatorial Committee.

Some of the Democrats’ top recruits were not as strong as they initially appeared to be.

Strategists thought former Ohio Gov. Ted Strickland was well-positioned to knock off Portman, but his campaign floundered over the summer as his gubernatorial record became a serious vulnerability.

Rep. Patrick Murphy (R-Fla.) was another highly touted recruit, but his youth, thin record and misleading claims about his professional background as a certified public accountant hurt his bid against Rubio.

Meanwhile, several Senate Republicans helped themselves by running especially effective campaigns.

In Ohio, Portman emphasized his record of accomplishment by pointing to more than 45 bills signed into law by Obama, and his campaign also recruited 2,000 volunteers who made more than 6 million voter contacts.

In Pennsylvania, Toomey artfully weaved between Trump and Clinton, knowing he had to appeal to pro-Trump voters in rural areas and pro-Clinton voters in the cities.

His campaign ran an ad in Philadelphia touting the praise of Clinton’s running mate, Virginia Sen.Tim Kaine Timothy (Tim) Michael KaineButtigieg stands in as Pence for Harris's debate practice Trump meets with potential Supreme Court pick Amy Coney Barrett at White House Names to watch as Trump picks Ginsburg replacement on Supreme Court MORE (D), who applauded Toomey’s “seriousness, intellect and civility.” At the same time, it ran an ad in rural Wilkes-Barre slamming Clinton and pledging that Toomey would stop her from having a blank check.

In Florida, Rubio, who ran to the right in the Republican presidential primary earlier in the year, presented himself as more of a centrist and earned points by siding with Democrats against Republicans in the squabble over money to fight the Zika virus.

Democrats’ chances of taking back the Senate in the next election cycle are slim, as they will have to defend 25 seats, including in Republican-leaning states such as Missouri, Montana, North Dakota, Indiana and West Virginia.

Republicans only have to worry about eight seats in 2018.

Updated 3:20 a.m.