Prosecutor Ken Buck eked out a win in Colorado's Republican Senate primary Tuesday over former Lt. Gov. Jane Norton.

The AP declared Buck the winner. Buck won with 52 percent of the vote to Norton's 48 percent. 

Buck will face Sen. Michael BennetMichael Farrand BennetOvernight Health Care: GOP pushes stiff work requirements for food stamps | Johnny Isakson opens up about family's tragic loss to opioids | Republicans refuse to back vulnerable Dem's opioids bill | Dems offer new public option plan Lawmakers discuss Latino education gap The Hill's Morning Report: Hannity drawn into Cohen legal fight MORE (D) in November. 

The primary was too close to call heading into Election Day and it's one that will be remembered for some of the nastiest and most personal attacks of the primary season thus far.

Norton started off as the frontrunner, courtesy of her support from Republicans in Washington and backing from the National Republican Senatorial Committee (NRSC).

But in a cycle that has repeatedly punished candidates with insider status, that support became a negative as Buck started hammering Norton as the establishment pick.

His support, meanwhile, came largely from conservative and Tea Party activists as the establishment line caught on with GOP primary voters. But far from hiding behind her cash advantage, Norton went right after Buck's strength and hit him with several negative TV ads.

After Buck was caught on tape calling those who questioned whether President Obama was born in the United States "dumbasses," Norton hit him for "insulting" members of the Tea Party.

And after Norton suggested Buck wasn't "man enough" to run his own attack ads against her, instead standing behind third-party groups, Buck told supporters at a campaign event they should vote for him because he "doesn't wear high heels." That comment elicited another Norton negative spot.

Both candidates had endorsements from major figures in the Republican Party. Sen. John McCainJohn Sidney McCainHeitkamp becomes first Dem to back Pompeo for secretary of State Senate committee sets Monday vote even as Pompeo appears to lack support Trump checkmates Democrats in sending Pompeo to North Korea MORE (R-Ariz.) campaigned with Norton the weekend before the race and conservative favorite Sen. Jim DeMint (R-S.C.) campaigned with Buck.

Despite a negative primary on the Democratic side, the Democrats are convinced the GOP contest has done plenty of damage to the nominee. Democrats, in-state and nationally, have catalogued the litany of statements from Buck over the course of the primary it thinks will alienate independent voters.  

In a Democratic Senatorial Campaign Committee memo e-mailed after Tuesday's results, Sen. Robert MenendezRobert (Bob) MenendezPoll: Menendez has 17-point lead over GOP challenger Russian attacks on America require bipartisan response from Congress Justice Dept intends to re-try Menendez in corruption case MORE (D-N.J.) said Buck "joins the ranks of Rand PaulRandal (Rand) Howard PaulHeitkamp becomes first Dem to back Pompeo for secretary of State Senate committee sets Monday vote even as Pompeo appears to lack support Trump checkmates Democrats in sending Pompeo to North Korea MORE, Sharron Angle, and Ron JohnsonRonald (Ron) Harold JohnsonGOP senator: Congress needs ‘to move on’ from Russia probe GOP senator: ‘Way too early’ to talk about supporting Trump in 2020 IG report faults fired FBI official McCabe for leak to media MORE as out-of-touch extremist candidates more concerned with imposing a strict social doctrine than with getting our economy moving again."  

NRSC Chairman John CornynJohn CornynSenate confirms Trump’s pick to lead NASA DOJ denies reports judicial nominee once called illegal immigrants 'maggots' Overnight Energy: Trump NASA pick advances after drama | White House office to investigate Pruitt's soundproof booth | 170 lawmakers call for Pruitt to resign MORE (R-Texas) countered by assailing Bennet's voting record during his time in the Senate, saying he "eagerly toed the party line and embraced the policies that helped drive our national debt past a record $13 trillion during his brief appointment to the U.S. Senate."

The general election race is considered a toss-up.

—Updated at 11:51 p.m.