Outgoing Republican Sen. Paul Formica’s retirement from public service left the opening Democrat Martha Marx needed to win the seat in a charmed third try.

Marx beat former state GOP chairman Jerry Labriola Jr. with 52.25% of the vote, according to unofficial numbers from the Office of the Secretary of the State Wednesday afternoon. Marx brought in 17,450 votes to Labriola’s 15,945.

Marx carried East Lyme, the town where Formica lives and owns a popular restaurant, by 53.52%. She took 69.36% of the vote in her home city of New London. She won Old Lyme with 52.36%.

Salem, Bozrah, Waterford, Montville and Labriola’s hometown of Old Saybrook went to her opponent.

Despite an incomplete return Tuesday night, Marx said she felt confident that she won.

“It feels really, really good,” she said. “I have worked so hard for this.”

She attributed the win in large part to the momentum she gained and the relationships she built over her two previous runs as she tried to convince people she was the right person to represent them.

“I think, finally, enough people met me and realized I was right.”

She also credited reproductive choice as one of the issues driving voters to cast their ballots for her.

“I kept saying that throughout the whole campaign, how important choice was,” she said.

Marx is a two-term New London councilwoman and a former chairwoman of the Democratic Town Committee.

Labriola left a gathering of supporters at Flanders Fish Market in East Lyme Tuesday night without conceding the race or addressing those who came out for him.

He made a statement Wednesday morning.

“Last night was not the outcome many of us had hoped for,” he said. “But the people of the 20th have spoken and I will accept and respect their decision.”

He thanked his team, singling out Formica as a mentor and friend.

“I’m not sure what the future will bring but I plan on being very much involved throughout our great district. I will not be going away,” he said.

Marx in her two previous contests against Formica won 71% to 29% in New London but lost all other towns in the district. The voting majority outside of New London belongs not to Democrats or Republicans, but to residents unaffiliated with either major party.

Both candidates appeared on two lines of the ballot, Marx for the Working Families Party and Labriola for the Independent Party.

Marx, 59, is a registered nurse with the Visiting Nurses Association of Southeastern Connecticut. She grew up in Waterford and raised her four adult children in New London.

She made her bid for the seat in January, shortly after Formica announced his plans to retire. Labriola entered the race in May with Formica’s endorsement after months of speculation about who would step up.

What ensued was an aggressive campaign waged in mailboxes across the district with a barrage of fliers on each side casting the other as extremist. Marx emphasized Labriola’s stint as party chairman from 2011-15, while Labriola tried to capitalize on Marx’s opposition to a New London minimum police staffing ordinance amid the “Defund the Police” movement.

Marx campaigned on foundational issues including reproductive rights and affordability in two key areas: healthcare and housing. And amid the aggressive attacks from Labriola about police staffing, she emphasized a history of – and ongoing commitment to – fully funding police, firefighters and emergency medical technicians.

Labriola, 65, campaigned as an “independent voice” committed to constituents, not parties. He supports traditionally conservative agenda items like lower taxes, less government overreach and free market economics, but cited his support for reproductive rights and “common sense” gun laws passed in the wake of the Sandy Hook Elementary School shooting as evidence that he does not agree with Republicans on all the issues.

His campaign manager said late Tuesday that Labriola would not immediately have a statement.

Born and raised in Naugatuck as the son of a state senator, Labriola and his wife, Barbara, raised four daughters in Wallingford before moving to Old Saybrook about six years ago. He is a partner at Labriola Law Group with his brother, state Rep. David Labriola, R-Oxford.

e.regan@theday.com