Pressley is likely to become the first black woman elected to Congress from MA in November, since there are no Republican candidates in the race.
Capuano told supporters he did everything he could to win re-election.
Rep. Stephen F. Lynch easily won his Democratic primary Tuesday in his bid for a ninth full term. She became the first woman of color ever to serve in the city's council in 2010. In making his concession remarks, Capuano told his campaign team, "I will tell you Ayanna Pressley is going to be a good congresswoman and I will tell you that MA is going to be well served".
Massachusetts' last Democratic primary upset came in 2014, when Seth Moulton defeated Rep. John Tierney in the state's 6th Congressional District.
They moved to Brooklyn, and Pressley attended Boston University from 1992 to 1994, but left school to work full time at a hotel to support her mother.
"This is not just a blue wave; this is a movement that's coming to Congress", New York congressional candidate Alexandria Ocasio-Cortez said during a June appearance with Pressley, before either woman had defeated their supposedly safe Democratic opponents. "It matters who those Democrats are".
'Defeat will stay with me forever' says devastated Thiem
Nadal was very apologetic to his opponent as they embraced at the net following the marathon match. Defending champion Rafa Nadal failed to win a single game in the opening set of his U.S.
"I knew we would be essentially, alone", Pressley said during her victory speech.
"Our president is a racist, misogynistic, truly empathy-bankrupt man", Pressley told supporters on Tuesday night.
Liberal Democrats Andrew Gillum and Ben Jealous are vying to become the first black governors in Florida and Maryland, respectively, while Democrat Stacey Abrams would be the first black woman governor of any US state if elected in Georgia.
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.
The Democratic nominating contest fight between US Representative Michael Capuano, 66, and Boston City Councilor Ayanna Pressley, 44, was his first since 1998. She ran on a platform of abolishing ICE-that's the Immigration and Customs Enforcement agency-and speaking for prisoners behind bars.
Among other races, comedian Jimmy Tingle was trying to shift from political humor to political office as he runs for the Democratic nomination for lieutenant governor against Quentin Palfrey, a one-time aide to President Barack Obama.