Now, it’s a sprint to September.

At-large Metro Council member John Cooper finished as the top candidate in Thursday’s election, ending the day with a nearly 10-point advantage over incumbent Mayor David Briley.

The strong showing gives Cooper a distinct edge as he takes Briley to a Sept. 12 runoff and in the aftermath of the vote, both candidates have started the work to build new coalitions and shape the narrative for the weeks ahead.

Big cheers broke out at Cooper's election night watch party at the Elks Lodge in North Nashville as the first results came in with a lead he held all night. Supporters danced to "Brick House" and drank as they waited for Cooper to speak.

Sporting a no-tie look and kicking off his remarks by snapping a photo of his crowd with his phone, Cooper thanked his rivals and Briley for his leadership during a "disruptive time" for Nashville.

"I want to earn your vote and trust," Cooper said. "And we want a town where educator pay and police and firefighter pay come first. And infrastructure in your backyard comes first. That is what is progressive and what effective progressivism means."

As his wife and son stood next to him, Cooper said he would make education a priority for the city and have a transit plan in his first year.

"A Nashville for everyone. A Nashville that includes everyone and a Nashville where our children can take advantage of the opportunities of this great city, a city that still includes us,” Cooper said. “And it's about being a great city, a growing city and a city that nourishes all of its neighborhoods."

Cooper had 35.01% of the vote in Nashville's mayoral election, followed by Briley, a 17-month incumbent, with 25.3%, according unofficial election results.

Retired Vanderbilt professor Carol Swain has 21.89% of the vote, followed by state Rep. John Ray Clemmons at 16.08%.

A sitting mayor has never lost a reelection bid in the history of Nashville's Metro government. But past mayors have had a full, four-year term under their belts and had not entered office under the unusual set of circumstances Briley did.

Only one other incumbent Metro mayor has been forced into a runoff in a reelection effort. Beverly Briley — the current mayor's grandfather — went to a runoff during two reelection campaigns.

Briley suddenly on the defensive

As Cooper's advantage held, people at Briley's party at Woolworth's in downtown stood anxious, hoping to narrow the gap. A one-on-one runoff pitting Briley against Cooper is the worst-case scenario for the current mayor and his supporters, with Swain voters largely expected to support Cooper.

"Nashville is pretty unique right now," Briley said in a solemn voice. "We are a city that is prospering more than we ever have before. And that prosperity gives us a great opportunity to take care of more people."

Briley told reporters Thursday night that he is "looking forward" and trying to identify a future for Nashville that takes care of more people. He said he believes Cooper is looking "backwards."

"(Cooper) tries to second guess things that have happened in the past, looks to blame people for things that may not be going right," Briley said. "And I just don't think that's good for the city."

He tied the council member's approach to a “national trend" of divisiveness.

“When you try to divide, one part of the community against the other, is really sort of symbolic of the national trend to divide one group against the other. And I think that's not productive," Briley said.

Clemmons was the first of the candidates Thursday night to concede. His family joined him at Fort Houston as he thanked his supporters in an emotional speech.

"I consider both of these gentlemen good friends," Clemmons said of Cooper and Briley. "I've known them for a long time, and I've already spoken to them this evening and wish them the best of luck in the runoff ahead."

Clemmons tearfully told the crowd that his campaign was not about him but about Nashville and what residents wanted.

Swain congratulated Cooper and Briley, saying that "the people have spoken."

“We will respect that. The results of this election is not a rejection of the values we believe in, that we fought for,” she told her supporters at Millenium Maxwell House Hotel.

“I will remain active as your voice.”

Four candidates dominated campaign

This year's mayoral election featured 10 candidates, but the four leading contenders dominated the campaign. Those candidates spent, combined, more than $1.6 million — hundreds of thousands of dollars on television commercials and campaign mailers in the last several months.

The frontrunners, Briley and Cooper, raised nearly $1.18 million and $312,000 respectively, spending $992,000 and $1.6 million during the campaign season.

Cooper largely self-funded his race, significantly bolstering his campaign with nearly $1.5 million in his own money. He was the last major candidate to enter the race, announcing his candidacy in April after initially saying he would not run.

Cooper's critics have accused him of attempting to "buy the race," while those opposed to Briley have pointed to the more than $270,000 he's received in campaign contributions from developers, real estate investors, designers, brokers, property managers and other industry representatives this year.

Nashville voters were also on track to approve two ballot measures Thursday, which would require more budget information from the city and change how appointments are made if there are vacancies on the Metro school board.

Cooper blasted city deals; Briley pushed progress

Cooper, who serves in a countywide council seat, has been a thorn in the side of Briley — and former Mayor Megan Barry before him — challenging the city's decisions in several high-profile deals.

He fought the $15 million for public infrastructure at the Nashville Yards project where an Amazon operations hub is locating, as well as the relocation of the National Museum of African American Music within the downtown Fifth + Broadway project.

He blasted the Metro Development and Housing Agency project to give $7.9 million to a mixed-use development in Rolling Mill Hill, but that plan was ultimately approved.

If elected, he says he wants to redirect the city's attention and growth to its neighborhoods.

Cooper has cast himself as a policy wonk — though Briley supporters claim that title belongs to Briley — and a businessman who would cut down city funding for development and make better deals for the city.

He set out to paint Briley as someone driven foremost by development.

Briley sought to position himself as the best candidate to continue Nashville's progress. He touts his biggest successes in office as the Under One Roof 2029 affordable housing plan and the Nashville GRAD, a program aimed at helping cover needed expenses for community college students.

Briley took over when Barry resigned in March 2018 amid scandal, and he won a special election in May of that year to serve out the remainder of her term.

A full, four-year term, Briley says, will give him the time he needs to make real progress on the issues he has laid out as priorities: affordable housing, public education, transit and workforce development.

Swain has been critical of Briley, Cooper and Clemmons, a Democratic state representative who represents Nashville, as the "status quo," while Clemmons criticized the two for not making the serious investments needed in education and other areas.

Clemmons was the only candidate to support a budget proposal considered by the Metro Council this year to increase the property tax rate by 19%, largely for funding for Nashville schools. He blasted Briley's spending plan, which for the second year did not include a tax hike, and Cooper for not supporting an increase.

Can Cooper unseat Briley?

Briley and Cooper will have just weeks to build on their coalitions and draw from Clemmons and Swain supporters. Early voting begins Aug. 23 ahead of the Sept. 12 runoff.

Though city elections are nonpartisan, political affiliations came into play in the four-way contest and will continue to shape the election in the coming weeks with Swain supporters likely to back Cooper in the runoff.

Cooper, though a social centrist, has largely campaigned on fiscal conservatism and racked up support from Nashville Republicans and conservatives.

Briley had strong fundraising leading up to the general election, which he'll need to continue in the days ahead. Cooper has struggled to gain traction in fundraising but thanks to self-financing, outspent Briley by a more than two-to-one advantage in the weeks leading up to Thursday.

Briley has work ahead of him with Cooper able to send more money into his campaign in the next few weeks.

A runoff is going to cost Nashville, too. The Davidson County Election Commission estimated a $900,000 price tag for the general election but will have to calculate what the runoff will cost based on how many council races will go to runoff.

About 110,900 voters turned out for Nashville's 2015 runoff election — nearly 6,000 more than those who voted in the general election.

Adam Tamburin, Natalie Allison, Holly Meyer and Jason Gonzales contributed to this report.

Yihyun Jeong covers politics in Nashville for USA TODAY NETWORK - TENNESSEE. Reach her at yjeong@tennessean.com and follow her on Twitter @yihyun_jeong.