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 BennetColorado senators pitch immigration compromise Colorado senators mark Olympics with Senate hallway curling GOP Senate candidate fundraising lags behind Dems in key races 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 McCainLawmakers worry about rise of fake video technology Democrats put Dreamers and their party in danger by playing hardball Trump set a good defense budget, but here is how to make it better 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) MenendezJustice Dept intends to re-try Menendez in corruption case DACA is neither bipartisan nor in America's interest Senate DACA deal picks up GOP supporters MORE (D-N.J.) said Buck "joins the ranks of Rand PaulRandal (Rand) Howard PaulDem wins Kentucky state House seat in district Trump won by 49 points GOP's tax reform bait-and-switch will widen inequality Pentagon budget euphoria could be short-lived MORE, Sharron Angle, and Ron JohnsonRonald (Ron) Harold JohnsonTrump spars with GOP lawmakers on steel tariffs Overnight Regulation: Trump unveils budget | Sharp cuts proposed for EPA, HHS | Trump aims to speed environmental reviews | Officials propose repealing most of methane leak rule Trump budget seeks savings through ObamaCare repeal 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 CornynLawmakers feel pressure on guns Kasich’s campaign website tones down gun language after Florida shooting Murphy: Trump’s support for background check bill shows gun politics ‘shifting rapidly’ 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.