Two progressive Wu-backed candidates in the closely-watched District 5 and 6 races were elected Tuesday night, with Enrique Pepén and Benjamin Weber declaring victory.

Pepén, the mayor’s former head of the Boston Office of Neighborhood Services, defeated the more conservative Jose Ruiz, a retired 29-year officer with the Boston Police Department while Weber, a workers’ rights attorney, edged the more moderate William King, an information technology specialist.

“I’m so grateful for the outpouring of support I have received from day one,” Pepén told a crowd of supporters in Roslindale Tuesday night. “I am ready to serve District 5.”

In Jamaica Plain, Weber stated that he couldn’t “believe we did this,” while characterizing his victory and the support he received in District 6 as the “most special thing I’ve ever been a part of.”

“We were able to send a message, and we’ll hopefully have a City Council that we’re going to be proud of,” said Weber, who spoke about the need to fix the body’s dysfunction in the weeks and months leading up to the day’s election.

Pepén and Weber will replace the embattled incumbents Ricardo Arroyo and Kendra Lara, who were knocked off in the September preliminary after a series of widely publicized ethical and legal lapses.

Mayor Michelle Wu, who stated earlier in this election cycle that the lapses had damaged the credibility of the City Council, again addressed the negative “headlines” that became so entrenched in the District 5 and 6 races.

“It’s unfortunate to hear that in so many parts of the city people were disappointed in the headlines that kept coming out,” Wu said while attending an election night party for Pepén. “I think we have councilors-elect here who are not only eager to bring that vision and needed action for our residents, but have the experience, the track record of getting things done in their communities and City Hall.”

The two races pointed to a potential progressive sweep for Wu, who wasn’t on the ballot, but ensured that she was a factor in the day’s Council races, backing four candidates — Pepén, Weber, Sharon Durkan for Districts 5, 6, and 8, respectively, and at-large candidate Henry Santana — in her bid to reshape the body.

Durkan was far ahead in District 8 shortly before 10 p.m., but the race was much tighter for the fourth at-large seat, where Santana, Wu’s former director of civic organizing for the city, was facing Bridget Nee-Walsh, a “right-of-center” union ironworker who lives in South Boston.

In District 5, Wu’s endorsement of Pepén ultimately carried more weight than the backing Ruiz received from former Marty Walsh, who had worked with the former police officer during his time in office.

Pepén said he would be focused on the affordability of the district, in terms of not only making sure residents there could pay their rent but ensuring that there was a pipeline to homeownership.

He also talked about enhancing public school education, both in academic rigor and infrastructure investments, and providing constituent services, which he felt had been lacking.

“I want to be a boots-on-the-ground councilor,” Pepén told the Herald Monday. “It’s how I like to carry myself. I like to do face-to-face encounters. I love to just make sure that I know my district like the back of my hand.”

Ruiz also spoke about improving upon basic city services that were lacking. Throughout the campaign, he said he noticed that other candidates were repeating some of his ideas, in terms of his priority areas, but was unsure whether that would help or hurt him in the final leg of the race.

“My impact’s already felt,” Ruiz said on Monday. “If people are repeating my answers, then would you rather just have someone saying that’s a great idea, I’m going to carry his idea, or don’t you want the person who actually was brave enough to say it from the beginning?”

In District 6, Weber also benefited from the mayor’s endorsement. This particular race was expected to be split largely along neighborhood lines, with Weber residing in Jamaica Plain and King living in West Roxbury, their respective chosen election night party locations.

“I think I’ve run a campaign that I can be proud of,” Weber said Monday, noting that he would be focused on improving the city’s public schools for families across the district and working to bring about a Council “that everyone in the city can feel proud of.”

King said he felt confident heading into the election, but thought it was “going to be a very close race.” He was hopeful, however, that the votes were not dependent on where each candidate resides.

“The last thing I want this race to be is a West Roxbury vs. JP,” King said. “I think that we really need to be focused on uniting the district.”