BOSTON (AP) -- In a political stunner, incumbent Democratic U.S. Rep. Michael Capuano lost Tuesday's primary to Ayanna Pressley, a Boston city councilor who is virtually assured of becoming the first black woman to serve Massachusetts in Congress.
The 44-year-old's upset over a 10-term incumbent congressman underscores the shift underway in a Democratic Party whose base is seeking younger, more diverse candidates who embrace liberal policies. Her victory comes just two months after Alexandria Ocasio-Cortez similarly defeated a top House leader in a primary for a New York congressional seat.
Ocasio-Cortez on Tuesday night tweeted a selfie of both women together and wrote, "In June, I won my primary. Tonight, she won hers. Here's to November." A Pressley campaign insider, meanwhile, posted a video showing the candidate the moment she learned she'd won.
Pressley, the first black woman to serve on the council, is now on track to represent an area of Massachusetts once served by Democratic icons Tip O'Neill and John F. Kennedy.
"Change is coming and the future belongs to all of us," Pressley told wildly cheering supporters Tuesday night.
A subdued Capuano told supporters he did everything he could to win re-election.
"Apparently the district just is very upset with lots of things that are going on. I don't blame them. I'm just as upset as they are, but so be it. This is the way life goes," he said.
The race between Capuano and Pressley was perhaps the most closely watched contest in Massachusetts, especially since Pressley drew comparisons to Ocasio-Cortez.
The 7th Congressional District is the only one in the state where minorities comprise a majority of the population.
"This is a fight for the soul of our party and the future of our democracy," Pressley said Tuesday while campaigning in the district. "And a reliable vote is not good enough."
Capuano is considered one of the most liberal members of the Massachusetts delegation, and Pressley had acknowledged she had few major policy quarrels with him.
There is no Republican on the November ballot in the district, meaning Pressley is virtually assured of entering Congress in January.
Massachusetts' last Democratic primary upset came in 2014, when Seth Moulton defeated Rep. John Tierney in the state's 6th Congressional District.
Democratic U.S. Sen. Elizabeth Warren sailed through her primary unopposed. She'll face Geoff Diehl, a state representative who served as co-chairman of President Donald Trump's 2016 campaign in the state and defeated two other Republicans for his party's nomination.
Another veteran congressman, Democratic Rep. Richard Neal, won a spirited primary showdown with Tahirah Amatul-Wadud, a black attorney from Springfield who had hoped to become the first Muslim to serve in Congress from Massachusetts. Neal, the dean of the state's House delegation, first was elected in 1989.
Two other Democratic House incumbents, William Keating and Joe Kennedy, fended off primary challenges on Tuesday. Kennedy, the grandson of the late U.S. Sen. Robert F. Kennedy, delivered the Democratic response to Trump's State of the Union address earlier this year.
Another Democrat, U.S. Rep. Niki Tsongas, is retiring at the end of this term, and that open seat touched off a political scramble with 10 candidates on the Democratic primary ballot.
Republican Gov. Charlie Baker won his party's nomination for a second term, defeating Scott Lively, a conservative minister and staunch supporter of Trump who frequently called Baker — a frequent critic of the president — a RINO, or Republican in Name Only. Baker will face Democrat Jay Gonzalez in November.
Baker, a moderate who has been popular with voters in what is perceived as one of the nation's bluest states, will face Gonzalez, who served as secretary of administration and finance under Democratic Gov. Deval Patrick.
"At a time when our country is having trouble finding common ground on so many issues, we in Massachusetts are the exception," Baker told supporters. "We believe that people in public life can, and should, debate the issues respectfully and seek common ground whenever possible."
Neither Gonzales nor his primary opponent Democrat Robert Massie, a longtime political and environmental activist, was well-known outside party activist circles. Both contended that Baker's support among voters was soft and that his administration had failed to make significant strides in many areas, particularly the problems plaguing the Boston-area transit system known as the "T."