Mayor Martin J. Walsh enters the general election in approximately the same shape he was in at the start of the campaign — as a strong incumbent with a massive financial advantage.

But something even more tantalizing appears within Walsh’s grasp: the possibility that he could reprise, and even expand, the coalition that first elected him in 2013 and made his predecessor the city’s longest-serving mayor.

After piling up 63 percent of the vote to City Councilor Tito Jackson’s 29 percent in Tuesday’s preliminary election, Walsh will face an electorate that will expand and change shape in the six weeks before November’s final. But the inroads he made Tuesday in the city’s largely minority neighborhoods echo an earlier alliance — one even more notable because he is facing the first black mayoral finalist in four decades.

Four years ago, Walsh expanded westward from his Dorchester and South Boston base into the city’s central neighborhoods to seize his first term. In doing so, he answered questions about whether an Irish-American state representative from Savin Hill could increase his appeal beyond his geographic and pro-union base.

On Tuesday night, Walsh boasted that he had beaten Jackson in 66 of the 97 precincts that make up the city’s communities of color. He even squeezed out a slender win in the Roxbury-based district that Jackson has represented since 2011, according to unofficial results.

To be sure, just 14 percent of registered voters turned out Tuesday, and low turnouts almost always favor incumbents. In coming weeks, Jackson could capitalize on increased media attention and the typical tightening that come as Election Day nears. The mayor, a street-smart pol not celebrated for his rhetorical talents, could stumble.

But if Walsh can continue to expand his appeal, he could approach something far more useful: a governing majority that, like his predecessor’s, looks beyond the city’s old political and tribal boundaries. Thomas M. Menino, the first non-Irish mayor in generations, tended to groups that had long felt shut out of the city’s political establishment: African-Americans, the city’s gay population, even conservatives in East Boston.

It made Menino virtually invincible on Election Day.

“That was a big part of his success, undoubtedly, that he had such a stronghold in the minority vote,’’ said Jack Beatty, a political historian who co-wrote Menino’s autobiography. “He called himself the mayor for a new America, and that’s the new America, right from the first election.’’

In the 2013 preliminary elections, a wide-open race, three prominent candidates of color earned the most votes in nine of Boston’s 22 wards. While Walsh and his eventual November rival, then-City Councilor John Connolly, feasted on the city’s outlying wards, the inner neighborhoods went to Charlotte Golar-Richie, then-Councilor Felix G. Arroyo, and John Barros.

When the race was whittled to Walsh and Connolly, Walsh — with that trio’s backing — took seven of those nine innermost city wards.

In Roxbury-based Ward 12, for instance, those three contenders grabbed more than 60 percent of the vote in the 2013 preliminary; Walsh went on to beat Connolly by 17 percentage points there in the final.

On Tuesday, despite it lying entirely within Jackson’s council district, Walsh only lost Ward 12 by 221 votes.

Walsh also defeated Jackson by 228 votes in Ward 8, a Roxbury/South End swath that sits mostly in Jackson’s district. That was nearly the identical margin he posted there over Connolly in the final four years ago.

This year’s matchup between a white incumbent and an African-American challenger, the first mayoral final since 1983 that has featured candidates of different races, comes amid a sometimes contentious national conversation on race. But both Jackson and Walsh publicly appear eager to defuse that dynamic, reaching out to voters of all kinds.

Meanwhile, the city, with its rapidly evolving demographics, has matured politically. In Charlestown, for example, long a bastion of white-ethnic politics, the neighborhood gave its vote both to Walsh and to Lydia Edwards, an African-American lawyer from East Boston running for City Council. Throughout the district, which also includes the North End, Edwards placed a close second behind a white male candidate backed by Walsh.

In a press release last week, Jackson senior adviser Ron Bell laid out the case for a Jackson victory in November, pointing to the state’s first African-American governor, for whom Jackson worked as an aide.

“In some ways Tito Jackson is more connected to the community than Governor [Deval] Patrick was,’’ Bell wrote. “He is from the city of Boston. He was adopted by parents who are well-known Boston community activists. He can resonate with the issues because he grew up in Roxbury’s historic Grove Hall, an urban neighborhood in the heart of Boston.’’

But Walsh comes into the final six weeks with a stark cash advantage. By Sept. 15, the most recent reporting date, Jackson had just over $57,000 in his campaign account. Walsh, according to state campaign finance officials, counted nearly $4.2 million.

And while Tuesday was the first time Walsh’s name had appeared on a ballot in nearly four years, the night was not his first political test, and his record has been mixed.

After the 2016 presidential primary, the mayor’s team boasted privately that Boston — meaning the mayoral machine — had put Hillary Clinton over the top against Bernie Sanders. Indeed, while Clinton won statewide by just over 17,000 votes, she carried Boston by nearly 20,000.

Walsh’s operation was less effective the year before in battling grass-roots opposition to the city’s bid for the 2024 Olympics. Jackson was highly critical of that effort, which put Walsh in the unflattering light of appearing beholden to — or flummoxed by — downtown business interests.

Analysts said tapping the base of largely disaffected voters — upset with the Olympic failure, the education system, crime — could prove to be pivotal to the challenger’s hopes for November.

Joyce Ferriabough, a longtime Boston political consultant who has advised many African-American candidates and is supporting Walsh, said Jackson “can continue to put the spotlight on those things that really need some work, like income inequality, wealth-building, working on getting the violence in the community down, working toward integrating the police department and the fire department — all of these things that we know have plagued particularly communities of color.’’

But on those key issues, she credited Walsh with making progress.

Indeed, along with his profile-raising confrontations with President Trump and a massive development boom, Walsh has benefited thus far from a general satisfaction with city living. Of more than 390,000 eligible voters, only about 56,000 turned out Tuesday.

The hope for any candidate lagging so far behind an incumbent “is that somehow the political leanings of the electorate in November will be different than the political leanings of the electorate in September,’’ said Tom Keane, a former city councilor who said he is neutral in the race.

“But I don’t think that will happen,’’ Keane said. “More likely, in November, those people in the middle who didn’t come out will, and they’re more likely to favor the incumbent.’’

Jim O’Sullivan can be reached at jim.osullivan@globe.com. Follow him on Twitter at @JOSreports.