Minnesota Gov. Tim Walz made his final campaign stop in Gastonia, North Carolina, on Sunday -- where former President Donald Trump held a rally the day before.

Walz told an energized crowd the state is crucial to Vice President Kamala Harris' hopes for victory on Tuesday.

"We're going to win this thing, but we haven't won it yet," Walz said at RayNathan's, an iconic local barbecue restaurant in Gastonia.

"And for all of you, it's a privilege -- you are ground zero of how this thing can be won. Right through here, we win North Carolina, this thing's over."

The Trump campaign, Walz said, is closing out the campaign cycle in "absolute disaster, telling us that this country doesn't work, descending into madness and darkness and division, disrespecting our fellow citizens in Puerto Rico and across this country."

Walz also addressed Trump's Sunday suggestion that he shouldn't have left the White House after his defeat by President Joe Biden.

"Well, he didn't learn it then, but he's going to learn it on Tuesday," Walz said.

-ABC News' Isabella Murray

Former President Donald Trump appeared on Sunday's NASCAR coverage, where he delivered a message focused on the economy in a one-minute clip.

"We've got to save our country, and it needs saving. It's in very bad shape. The worst economic numbers in generations,” Trump said, speaking directly to the camera while sporting his red MAGA hat.

Trump then declared: "We're going to end up in a depression based on what's been happening."

"Just remember Kamala and her friends broke it. I'll fix it. Most important election in the history," he said.

Trump’s appearance on NBC came as the network was required to follow FCC's Equal Time rule providing the same airtime as they allotted Vice President Kamala Harris during her "Saturday Night Live" appearance.

-ABC News' Lalee Ibssa, Kelsey Walsh and Soo Rin Kim

Attendees at Vice President Kamala Harris' rally in East Lansing, Michigan, on Sunday, told ABC News that they were confident in Harris' prospects because they knew Republicans in their community who are casting a ballot for Harris -- many of them secretly.

Andrea Galindo said she believes Harris will win "because I know a lot of Republicans voted Democrat."

Similarly, Linda Brundage, who has voted in 16 presidential elections, said she is sure that in her community, "Some of the people who say they’re red will vote blue."

Another attendee, Mike Arvizu, said his father-in-law is a lifelong Republican who is voting for Harris. "If my father-in-law can do it, there’s a lot more people out there," Arvizu said.

These voters' sentiments reflect a defining strategy of the Harris campaign: to reach every possible voter in battleground states, including Republicans and independents. In her final rally speeches, the vice president stressed that she would invite those who disagree with her to have a seat at the table.

-ABC News' Selina Wang

Vice President Kamala Harris' campaign said it had more than 90,000 volunteers knock on more than 3 million doors across all the battleground states over the weekend.

-ABC News' Gabriella Abdul-Hakim