WASHINGTON (AP) — Joe Biden delivered decisive wins in Missouri and Mississippi on Tuesday, dealing an early blow to Bernie Sanders on a night when six states were up for grabs.

Both men were focused intensely on Michigan, the night’s biggest prize. That’s where the Vermont senator scored an upset that lent much-needed credibility to his 2016 primary challenge of Hillary Clinton — and where President Donald Trump’s victory four years was so narrow that Democrats are desperate to show they have the strength to flip it back. The former vice president made a final push there in recent days, rallying autoworkers and touting a fresh round of high-profile endorsements.

Beyond Michigan, Sanders could get a boost in Idaho, North Dakota or Washington state, where polls haven’t yet closed.

Even as the contours of the race took shape, the campaigns faced new uncertainty amid fears of the spreading coronavirus. Sanders and Biden both abruptly canceled public events in Ohio that were scheduled for Tuesday night. Sanders’ campaign said all future events would be decided on a case-by-case basis, while Biden called off a scheduled stop in Florida. The Democratic National Committee also said that Sunday’s debate between Sanders and Biden would be conducted without an audience.

Tuesday marked the first time voters weighed in on the Democratic contest since it effectively narrowed to a two-person race between Sanders and Biden. It was a test of whether Sanders can broaden his appeal among African Americans after earlier setbacks in the South. Biden, meanwhile, sought to show that he can keep momentum going after his surprise Super Tuesday turnaround.

With 125 delegates at stake, Michigan got most of the attention Tuesday. Trump won the state by only about 10,000 votes during the general election in 2016, and Democrats are eager to take it back.

A win for Biden might show his party he can do it again against Trump in November. But Sanders presented himself as a credible alternative and aimed to block Biden from piling up a wide lead in delegates to the Democratic National Convention this summer in Milwaukee.

Sanders has predicted victory in Michigan and scrapped a scheduled Mississippi stop to spend more time there. Biden went there less frequently, but sought late-breaking support there and toured an auto plant in Detroit on Tuesday.

“You’re the best damn workers in the world!” Biden shouted through a megaphone at the auto plant as workers in hard hats chanted, “Joe! Joe!”

Biden ticked off the names of six former presidential rivals who have endorsed him just in the past week, saying he is “the candidate that they think can win.” The former vice president has campaigned in recent days with two of them, Sens. Cory Booker and Kamala Harris, and appeared with Michigan Gov. Gretchen Whitmer. All three have been mentioned as possible vice presidential picks if Biden wins the nomination.

The confidence Biden exudes is a remarkable turnaround for someone who just two weeks ago looked to be falling too far behind Sanders to catch up. Now he’s trying to present an air of inevitability as the primary race’s winner.

It wasn’t all good feelings, though. At the auto plant, Biden was interrupted repeatedly by protesters angered by his support for the North American Free Trade Agreement and reluctance to embrace sweeping environmental proposals outlined in the Green New Deal. In a scuffle with demonstrators, Biden senior adviser Symone Sanders was knocked to the ground but unhurt.

Biden also endured a testy exchange with a worker who accused him of “actively trying to end our Second Amendment right.” Biden responded, “You’re full of shit,” and went on to say that while he supports the Second Amendment, “Do you need 100 rounds?” His gun control plan reinstates the assault weapons ban and includes a voluntary buyback program for assault weapons, stopping short of a mandatory buyback program that some of his opponents had supported in the primary.

Although he has rejected notions he could drop out of the race if Tuesday goes badly, Sanders says he is now battling the “Democratic establishment.”

“In a general election, which candidate can generate the enthusiasm and the excitement and the voter turnout we need?” Sanders asked.

Detroit neighbors Fayette Turner and Margaret Marsh were split on which to support: Turner voted for Sanders on Tuesday, while Marsh voted for Biden. But they agreed on one thing: the desire to beat Trump.

“Anybody but Trump,” Turner, 64, said. Marsh, 69, said her family has identified as Republican her entire life — until Trump took office.

“I think Biden’s the sanest one left,” Marsh said. “Hopefully he’ll have a good vice president.”