Boston City Council member Ayanna Pressley beat a 10-term incumbent Tuesday to win the Democratic nomination for Massachusetts’ 7th Congressional District, an upset building on the momentum for progressives sparked by Alexandria Ocasio-Cortez’s victory in a New York House primary earlier this summer.

Rep. Michael Capuano (D-Mass.) conceded to Pressley on Tuesday evening.

“Clearly the district wanted a lot of change,” he told supporters after his loss. “I’m sorry that this didn’t work out.”

Watch Pressley learn that she won Tuesday night:

With no Republican on November’s ballot for the district, Pressley is all but guaranteed to make history as the first black congresswoman from Massachusetts. Pressley, 44, already broke barriers in 2009 when she became the first woman of color elected to the Boston City Council.

Capuano first won his House seat in 1998. The 7th District encompasses most of Boston and much of Cambridge.

Facing an uphill battle against Capuano ― a poll for radio station WBUR showed her trailing him by 13 percentage points a month ago ― Pressley campaigned on the need to change the House’s status quo.

“I’ve been told to wait my turn,” Pressley said at a campaign event earlier this year. “I’ve been called a traitor for challenging an incumbent, told simply this isn’t the way things are done here.”

But, she added, “When the challenges we are confronted with are this big, this deep, and growing, I can’t and I won’t wait my turn.”

Those rallying to her cause included Ocasio-Cortez, the political newcomer thrust into the national spotlight when she upended veteran Rep. Joe Crowley, a House Democratic leader, in New York’s June 26 primary. Fresh from her win, Ocasio-Cortez tweeted, “Vote her in next, Massachusetts,” referring to Pressley.

Pressley’s campaign had dispatched staffers to aid Ocasio-Cortez’s get-out-the-vote efforts. And Pressley has called the New Yorker “my sister in change.”

Congratulations to my sister in service, @AyannaPressley, on continuing her historic path into Congress tonight.



Let’s push together to make Medicare for All, tuition free college, & living wages a reality in America - all without corporate PAC money. 🇺🇸 https://t.co/o2SbtUkByS — Alexandria Ocasio-Cortez (@Ocasio2018) September 5, 2018

As in Ocasio-Cortez’s race, Pressley was a progressive woman of color challenging a white male lawmaker. Unlike Ocasio-Cortez, who was running against a more moderate Democrat in Crowley, Capuano is a member of the Congressional Progressive Caucus with a solidly left-leaning legislative record. Much of the race turned less on substantive policy differences and more on whether voters wanted a fresh face and a change in the district.

But one difference was that Pressley didn’t accept donations from corporate political action committees in her campaign. Her platform promoted progressive ideas like Medicare-for-all, debt-free college and abolishing Immigration and Customs Enforcement.

Capuano also touted his years-long support for Medicare-for-all. And he positioned himself as fervently anti-Donald Trump ― refusing to attend the president’s inauguration last year, voting twice in support of impeaching him and frequently calling him out on Twitter. He was also well-known for his progressive views on foreign policy

The Boston Globe, the region’s major newspaper, gave Pressley their endorsement.

“I would like more women to consider government as a mid-career option, women who have been in our classrooms, running companies,” she told HuffPost Partner Studio in 2016. “Having greater parity, both racially and in gender [in government], is vital because solutions are more innovative when you have diversity of perspective and opinion and thought.”