Republican business owner Joe O’Dea jumped out to an early lead Tuesday night over state Rep. Ron Hanks, R-Cañon City, in the Colorado primary to decide who takes on Democratic U.S. Sen. Michael Bennet.

In preliminary, unofficial returns, O’Dea, the owner of a construction company, held a 9-point lead over Hanks, whose underfunded campaign was bolstered by unprecedented, heavy spending by Democrats.

“It’s the dawn of a new day in the colorado GOP,” state Rep. Colin Larson, R-Ken Caryl, told Colorado Politics after the Associated Press declared O’Dea had won the primary about 30 minutes after polls closed.

“Joe O’Dea is exactly what the people of Colorado want, and Michael Bennet and Joe Biden are probably wishing they saved their 10 million bucks for the general, because they’re going to need it.”

Outside groups aligned with Democrats spent at least $4 million on TV ads attacking O’Dea and calling Hanks “too conservative for Colorado” in what appears to have been a bid to boost the candidate Democrats believed would pose less competition to Bennet, who is seeking a third term.

Millions more have been spent by anonymous groups on mailers comparing O’Dea and Hanks in what appears to be an attempt to sway the GOP’s most conservative voters toward Hanks.

The wealthy O’Dea poured around $1.6 million into his own campaign in donations and loans and outspent Hanks by more than 10-to-1 through the most recent reporting period earlier this month.

O’Dea outlined the approach his general election campaign will take and said he intends to be “the Republican Joe Manchin,” invoking the Democratic senator from West Virginia who frequently breaks from his party’s caucus.

“Let there be no doubt, the Colorado Senate race is a referendum on Joe Biden’s policies and Michael Bennet’s rubber stamp,” O’Dea told supporters gathered Tuesday night at Mile High Station, a Denver event center he owns with his wife.

“America is struggling and moving in the wrong direction, and Joe Biden is to blame. Michael Bennet has been Biden’s wingman at every turn. Bennet votes with Biden 100% of the time,” he said. “Look, I love my wife, Celeste, more than life itself. But I don’t even agree with her 100% of the time.”

Added O’Dea: “I won’t vote the party line. Michael Bennet votes with the Democratic Party every time. I’ll be more like a Republican Joe Manchin; I’ll vote my conscience, I’ll make tough choices, I’ll ruffle some feathers, and I’ll always put America and Colorado first. No political party will own me. My agenda is common sense.”

In a fundraising email sent shortly after O’Dea claimed victory in the primary, Bennet slammed the GOP nominee’s opposition to any additional gun control measures and support for national Republican proposals to cut funding for Social Security and Medicare.

“[W]e know who Joe O’Dea is,” Bennet said in the email. “He’s given his own campaign seven-figures so he could buy his way onto the ballot, then he dumped more cash into attack ads to try and win this seat. He’s out of step with Coloradans, and he’ll be a rubber stamp for Rick Scott — who wants to raise taxes for low-income folks and seniors — and Mitch McConnell.”

National GOP Chairwoman Ronna McDaniel congratulated O’Dea and the other winners of Colorado’s Republican primaries and took a swing at their Democratic opponents in a statement.

“The policies of Colorado Democrats like Jared Polis and Michael Bennet have led to soaring inflation, record-high gas prices, and violent crime reaching a 25-year high,” she said. “Coloradans are ready to take a new direction away from the failures of Joe Biden and Colorado Democrats.”

A spokesman for the state Democratic Party called O’Dea too extreme for Colorado voters. 

“Joe O’Dea is hanging on by a thread after a tumultuous, costly primary where he highlighted his far-right positions that are out of step with Coloradans,” Nico Delgado said in a statement.

“O’Dea proved that he would be a reliable vote for MAGA Republicans to enact their dangerous agenda. Colorado Republicans are fractured while Democrats are united and ready to re-elect Senator Michael Bennet in November.”

Following a string of wins by Democrats up and down the ticket, Colorado isn’t considered the battleground state it was a decade ago and national forecasters have yet to rate Bennet’s reelection bid as competitive, but Republicans are banking that President Joe underwater approval ratings will be a drag on the incumbent.

Bennet won election to his second term by about 5 points in 2016, the same year Democrat Hillary Clinton carried the state by a slightly wider margin.

Watch: Former gubernatorial chief of staff on primary results