Boston City Councilor Ayanna Pressley, center, celebrates victory over U.S. Rep. Michael Capuano, D-Mass., in the 7th Congressional House Democratic primary, Tuesday, Sept. 4, 2018, in Boston. (AP Photo/Steven Senne)

In the latest blow to establishment Democrats, Boston City Councilor Ayanna Pressley defeated Rep. Michael Capuano for the nomination in Massachusetts’s Seventh Congressional District on Tuesday.

Pressley — who is running unopposed in November — will become the first black woman to represent Massachusetts in Congress, after serving as the first black woman to serve on the City Council. Capuano was a 10-term incumbent, representing a district covering an area stretching southwest from Boston. Capuano conceded Tuesday evening.

The race was compared to the Democratic primary in New York’s 14th District, which also featured a woman of color, endorsed by the Justice Democrats, running against an older, white, male incumbent. But there were clear differences. New Yorker Alexandria Ocasio-Cortez was a first-time candidate, while Pressley has served on the City Council since 2009. Although she was endorsed by progressive groups, Pressley, who has worked for Sen. John Kerry and supported Hillary Clinton in the 2016 election, is not as far left as Ocasio-Cortez, a Democratic Socialists of America member who organized for Bernie Sanders. The two women met at a fundraising event in New York in June, and Pressley referred to Ocasio-Cortez as her “sister in change.”

Another difference is that while New York Rep. Joe Crowley didn’t take Ocasio-Cortez’s candidacy seriously and skipped debates with her, Capuano recognized the threat from Pressley from the start. Last month the congressman talked to Yahoo News after a full day of campaigning in the district and said he had canceled an annual January vacation to focus on Pressley’s challenge. The two candidates debated several times in August.

Capuano picked up a number of key endorsements, including the other six Massachusetts House members, Boston Mayor Marty Walsh, former Massachusetts Gov. Deval Patrick and Rep. John Lewis, the civil rights icon. But Pressley chipped away at his lead, holding Capuano to a draw in the competition for endorsements from Massachusetts’s two powerful senators, Elizabeth Warren and Ed Markey, who stayed neutral. Then more endorsements fell her way, including state attorney general Maura Healey and both of Boston’s daily papers, the Globe and the Herald.

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“Voters might be hesitant to move on from Capuano after his years of experience and the seniority he has accumulated in Congress,” wrote the Globe editorial. “But Pressley is a proven advocate with an understanding of the needs of the district, and she would be a fresh voice in Congress. Pressley represents the present of the Seventh District and the future of the Democratic Party. She will serve the district well in Congress.”

The result of this race isn’t likely to change many votes in Congress — Capuano’s record checked nearly every box for a progressive Democrat — but it does change representation. Pressley’s campaign emphasized her ethnic identification with the district and focused on inequality within the district, as she emphasized in a video released early last month.

Pressley said Ocasio-Cortez’s victory in June was a boost for her campaign, getting some skeptics off the fence and further emboldening those who were already supporting her. She said the network of insurgent, progressive candidates being supported by groups like the Justice Democrats had been inspiring.

“I think it’s a return to the roots for the party,” said Pressley in an interview last month, “and it’s necessary for us to not only confront and resist what is coming out of this White House every day but to progress, not only in our communities but to advance our democracy.”

The Seventh District was once represented by John F. Kennedy and Tip O’Neill and is one of the most progressive in the country.