DETROIT—Under the most aggressive and well-financed attack of this campaign by rivals aiming to blunt his momentum, Donald Trump notched two victories Tuesday night, stretching from the Deep South to the Rust Belt.

The wins in Mississippi and Michigan will help to propel Trump into next week’s first winner-take-all contests in Florida and Ohio, which will serve as judgment day for hometown sons Marco Rubio and John Kasich, respectively.

Kasich, the two-term governor of Ohio who viewed Michigan as home turf, vied with Ted Cruz for a distant second to Trump. The results add pressure to Kasich he heads back home to compete and raise questions about his Midwest strength.

Kasich had spent more time in Michigan than any other candidate—so much so that he joked at various events in recent days that he might have to start paying taxes in the state. But since delegates are awarded proportionately here, and exit polls found late-deciding voters swung his way, the campaign viewed the finish as a springboard into Ohio on March 15, where the governor believes a win is eminent and will serve to reset the race.

“We are going to win the state of Ohio, and it will be a whole new ballgame,” Kasich, who has not yet won a state, said at his election night rally in Columbus.

The returns marked another poor showing from Rubio, who did not meet the threshold requirement in Michigan to win any delegates. The Florida senator has struggled in recent days to gain traction in the primaries, though he did win Puerto Rico over the weekend.

Still, he has watched chief rival Cruz not only eclipse him in several states but also manage victories over Trump. What’s more, Kasich, whom Rubio urged to leave the race, is gaining traction nationally. A new NBC/Wall Street Journal poll released Tuesday found Kasich beating Rubio for third place in the nomination fight, with Trump in the lead and Cruz in second. “In the contest going forward, the three of us that remain, we are in a virtual dead heat,” Kasich said, discounting Rubio.

Rubio has been camping out in his home state, where he is hoping to pull off an underdog victory. “I believe with all my heart that the winner of the Florida primary next Tuesday will be the nominee of the Republican Party,” he told supporters in Ponte Verde on Tuesday. Trump leads him in the polls there and has called Florida “his second home.” The GOP front-runner held a victory night infomercial-like press conference at one of his hotels in Jupiter, 90 miles from Rubio’s home base of Miami.

Both Kasich and Rubio hope home-state wins keep them in the game to prevent Trump from racking up the 1,237 delegates needed to secure the GOP nomination. Both are aiming for a contested convention. Ohio’s 66 delegates and Florida’s 99 delegates would help them in that fight. Cruz is hoping to win the nomination outright, staying away from talk of a convention scenario that would be at odds with his outsider, anti-establishment brand. The Texas senator is actively competing in Florida, and his presence there could weaken Rubio’s showing.

Trump’s victories on Tuesday, however, come after party leaders and activists banded together against him, forming the so-called “Never Trump” coalition. Former GOP standard-bearer Mitt Romney urged Republicans to vote against him in the upcoming primaries, and voiced robo-calls for Kasich, Cruz, and Rubio. Anti-Trump super PACs spent roughly $13 million against him, according to a report. And at the GOP debate in Detroit Thursday night, Rubio and Cruz sought to bring Trump down.

Trump saw Tuesday night as a resounding rejection of the effort. Facing such opposition, Trump urged Republicans to just rally around him, making a general election call to arms against Hillary Clinton.

“Let’s unify,” he said. “Let’s come together, folks. I am a unifier.”

Trump had led the polls in Michigan heading into Election Day and found the state to be friendly territory for him: Working-class, disaffected voters craving change and a political shakeup. Bernie Sanders carries similar appeal, particularly on issues such as trade and the economy, and overcame a 20-point deficit in the polls to claim an edge on Clinton.

Trump said his win in Michigan foreshadows his general election appeal. “I’m going to win Michigan” in November, he said, noting that he is bringing Democrats and independents to his side. “It’s the biggest story in politics today. I hope the Republicans will embrace it.”

But his rivals aren’t yet giving in—at least not now.

The Kasich campaign noted that 1,000 delegates will still be at stake after March 15. This week, the governor justified a contested convention if Trump did not win the necessary delegates.

Some of his supporters, however, are wary of what a contested convention would look like. “If they want to do that, they might as well vote for Hillary and save all their money,” said Dan Winslow, a farmer from Eaton Rapids who attended a rally Tuesday at a brewery in Lansing. ” It’s just going to weaken the Republican Party if they try to do that.”

“I’m concerned that it will look like the voice of the people is being stifled, and I don’t want that,” said Georgia Sharp, a Kasich supporter and chair of the Ionia County GOP. “Let’s hope it doesn’t end up that way.”