ST. LOUIS — City Treasurer Tishaura Jones won the St. Louis mayor’s race Tuesday, defeating Alderman Cara Spencer in a contest matching two progressive Democratic women.

Unofficial final returns showed Jones pulling in about 52% of the vote and Spencer about 48%.

“It’s time for St. Louis to thrive,” Jones, who will be the first Black woman to hold the office, told cheering supporters Tuesday night at the Omega Center in north St. Louis. “It’s time to bring a breath of fresh air to our neighborhoods.”

Jones reiterated that she will seek to address inequities in the delivery of city services and “will not stay silent” when she spots racism, homophobia, xenophobia or religious intolerance.

“I will not stay silent when I spot any injustice,” she declared.

Jones, 49, also said her campaign had “begun breaking down the historic racial barriers and the racial divides that exist and have existed for generations” in the city.

Spencer conceded at her watch party outside the Mahler Ballroom in the Central West End, surrounded by supporters.

“I’m proud to be a citizen of St. Louis tonight,” Spencer said. “The treasurer was my opponent but she is not my enemy. The people of St. Louis have spoken, and I pledge my support to Mayor-elect Tishaura Jones to move our city forward.”

Jones and Spencer each had said they were running to fundamentally change the way city government operates.

Jones entered the general election race as the favorite after finishing first in the four-way March 2 primary. Spencer, an alderman since 2015, came in second in the primary.

Jones emphasized her eight years’ executive experience as treasurer, citing her efforts to modernize parking operations, and five years before that as a state representative.

She also cited her existing relationships on the local, state and federal level, most notably with St. Louis County Executive Sam Page, who endorsed her.

Spencer, 42, portrayed herself as someone independent of old-style City Hall politics and as a foe of special interests, citing her leadership at the Board of Aldermen in fighting the leasing of St. Louis Lambert International Airport among other things.

Jones, who will become the city’s 47th mayor, will face some serious challenges, including violent crime underscored by a high murder rate.

She has said she wants to shift policing from an arrest and incarcerate model to a prevention model, expanding the use of mental health and other professionals to handle some 911 calls.

Jones also will have to deal with conditions at the main city jail downtown — which was rocked Sunday by rioting for the second time in two months.

But the new mayor also will benefit from a $517 million windfall coming to the city through a newly passed federal pandemic aid plan.

Jones in the campaign tapped the same mix of support from her home base in heavily Black north St. Louis and white progressives that she had in her near-miss 2017 mayoral bid and her winning campaigns for treasurer, most recently last year.

She also built momentum by trumpeting a steady stream of endorsements from liberal groups and a network of prominent Black elected officials across the country, including Kansas City Mayor Quinton Lucas.

Among them was Wesley Bell, the St. Louis County prosecutor, who was among those at Jones’ Tuesday night event.

“With Tishaura, you are going to see a lot more collaboration,” Bell told the Post-Dispatch. “She doesn’t have to build relationships. She’s already got them.”

Also on hand was Sara Weichold, a parking attendant. “As a Black woman, to see the first Black woman becoming mayor — it’s powerful to witness,” said Weichold, 41.

When news of Jones’ victory hit the crowd, music thumped and cheers erupted, including from Johanna Jones, 48, a lifelong friend of Tishaura Jones.

“I am amazed,” Johanna Jones said as the news set in. “I am overjoyed. I am proud. I am excited about what this means for St. Louis.”

In the campaign, both candidates took progressive stands to the left of more moderate Democrats such as Mayor Lyda Krewson, who didn’t seek a second four-year term this year.

However, Spencer also took pains to delineate herself from Jones, attacking some of Jones’ actions as treasurer, including awarding a controversial parking management contract to a past campaign donor. Jones said the firm was chosen in a competitive process.

Pro-Spencer TV commercials also attacked Jones for taking numerous trips at city expense from 2013 to 2016 and being among various city officials having a take-home vehicle. The Jones campaign said she turned in the vehicle in September 2016.

While Jones’ ads were positive, she did hit back at Spencer during joint appearances, criticizing Spencer for getting contributions from the local firefighters union after Spencer voted for a union-backed pension governance change.

Both campaigns were well-funded. As of early Tuesday, pro-Jones forces reported committing at least $1.07 million and Spencer backers at least $980,000. Those figures are for both the primary and general election campaigns.

The Jones side’s total included $85,000 from Collective Future, a national group promoting Black candidates, and about $26,000 from Higher Heights, a national group backing Black women running for office.

Also receiving some votes were two registered write-in candidates for mayor — Jerome Bauer, a frequent Green Party candidate in past elections, and businessman Nicholas Akerberg.

The election Tuesday was the second phase of St. Louis’ new nonpartisan voting system for municipal candidates passed as Proposition D at the election last November.

In the first phase, the March 2 primary, residents could vote for as many candidates for an office that they approved of, not just one. Backers said the idea was to qualify the candidates with the broadest support to move on to Tuesday’s general-election runoff.

In past April general elections, Democratic nominees usually rolled to landslide wins over Republicans and third-party candidates in the heavily Democratic city.

Jones will be sworn in on April 20, along with Comptroller Darlene Green, who won reelection without any opposition.

Rachel Rice and Jesse Bogan of the Post-Dispatch contributed to this report.