Rep. Alexandria Ocasio-Cortez conceded that Tuesday's primaries were a "tough night" for her chosen 2020 Democratic presidential candidate, Sen. Bernie Sanders.

Sanders suffered a series of devastating defeats, particularly in Michigan, a week after former Vice President Joe Biden clobbered him in the Super Tuesday contests.

"There's no sugar-coating it. Tonight's a tough night. Tonight's a tough night electorally," Ocasio-Cortez told about 8,000 viewers on Instagram Live on Tuesday night.

Ocasio-Cortez attempted to refocus the discussion away from leaders like Sanders to the power of the progressive grassroots, arguing that the left should "leverage" support for policies like single payer healthcare.

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Rep. Alexandria Ocasio-Cortez conceded that Tuesday was a "tough night" for her chosen 2020 Democratic presidential candidate, Sen. Bernie Sanders, who suffered a series of devastating primary defeats.

Former Vice President Joe Biden clobbered Sanders in Tuesday's key state, Michigan, which Sanders won in 2016 against Hillary Clinton. Biden also dominated in Mississippi and Missouri, while results from Washington, Idaho, and North Dakota still trickled in.

"There's no sugar-coating it. Tonight's a tough night. Tonight's a tough night electorally," Ocasio-Cortez told about 8,000 viewers on Instagram Live on Tuesday night.

But the congresswoman declared "generational" victory, arguing that the future of the party supports the kind of radical change she and Sanders are pushing for and has already won "enormous, decisive arguments on many, many issues."

"There's a generational divide in the Democratic Party on health care, on climate change, on foreign policy," she said, adding that the left should "leverage" support for bold policies to influence mainstream Democratic politics.

Ocasio-Cortez, who endorsed Sanders in October and has campaigned with him across the country, urged her supporters not to lose hope in electoral politics.

"Never, ever, ever let your heart turn black," she said, echoing a case she's made for years against cynicism among young people.

Towards the end of her livestream she took a question about her own presidential prospects and shot down the suggestion that she run for president in 2028.

"I want to level with all of you, I'm not a person that aspires to a position, I aspire to a mission," she said. "We can't swing from one savior to another. There's a lot of savior-ism in politics, like 'Who's next?' and 'Who's gonna save us?' And the answer is you. The answer is people."