(CNN) Alexandria Ocasio-Cortez, a 28-year-old Latina running her first campaign, ousted 10-term incumbent Rep. Joe Crowley in New York's 14th congressional district on Tuesday, CNN projects, in the most shocking upset of a rollicking political season.

An activist and member of the Democratic Socialists of America, Ocasio-Cortez won over voters in the minority-majority district with a ruthlessly efficient grassroots bid, even as Crowley -- the fourth-ranking Democrat in the House -- outraised her by a 10-to-1 margin.

This was the first time in 14 years a member of his own party has attempted to unseat Crowley, who chairs the Queens County Democrats. His defeat marks a potential sea change in the broader sphere of liberal politics -- a result with implications for Democrats nationwide that would recall, as optimistic progressives routinely noted during the campaign, former GOP Majority Leader Eric Cantor's loss to the insurgent, tea party-backed Dave Brat in June 2014.

"This is not an end, this is the beginning. This is the beginning because the message that we sent the world tonight is that it's not OK to put donors before your community," Ocasio-Cortez told roaring supporters on Tuesday night.

She cast her victory as the green shoots of triumph over the "deep midnight and darkness" of the political moment -- and a message to fellow progressive organizers that their brand of activism could succeed on a grander scale.

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