Making it official that a talented young candidate running on an unapologetic progressive agenda can unseat Democratic incumbents "who are ideologically and demographically out-of-touch with their voters," Alexandria Ocasio-Cortez on Tuesday night won her race for the U.S. House of Representative in New York's 14th District—making her the youngest female member of Congress ever elected and a leading voice among those pushing a much bolder agenda for the party.

After her historic primary upset over Rep. Joe Crowley this summer, Ocasio-Cortez's general election was seen as a formality in the Democratic stronghold, but progressives celebrated the election night victory nonetheless as an historic milestone and exciting development for the insurgent left.

"Ocasio-Cortez pulled off one of the biggest political upsets in American history and proved that America can still be a place where a working class woman of color can defeat a 10-term incumbent and his Wall Street-funded machine," said Justice Democrats communications director Waleed Shahid.

"One of the most important victories tonight belongs to Alexandria Ocasio-Cortez and the movement she has sparked," Alexandra Rojas,  executive director of Justice Democrats, added.  With the win, Rojas said, the progressive movement challenging the establishment of the Democratic Party has shown it "can unseat Democrats who are ideologically and demographically out-of-touch with their voters and forced Democratic elected across the country to stiffen their spines."

Ocasio-Cortez delivered her acceptance speech in New York just after 10pm ET.