SAN JUAN, P.R. – Marco Rubio had hoped to win this island’s Republican presidential primary Sunday, and was expected to do so by the other campaigns. But the way he won—in a landslide, with nearly 74 percent of the vote—gives the Florida senator the boost his supporters have been awaiting.

His showing means that Rubio claimed the 20 Puerto Rican delegates up for grabs Sunday; he already had the commitments of three at-large delegates there. Heading into Tuesday’s primaries in Michigan, Mississippi, and Idaho – Hawaii holds caucuses that day, but Michigan is the big prize – Donald Trump now leads the pack with 384 delegates, followed by Ted Cruz with 300, and Rubio with 151. All three, along with John Kasich (37 delegates), have vowed to take their fight to the convention in Cleveland this summer.

But if Rubio had lost this territory, which he visited Saturday, it’s doubtful he would have lasted that long.

“This is a great victory,” proclaimed José Fuentes Agostini, the Rubio campaign’s top official on the island. “It is here in Puerto Rico that we’re going to change the course of this presidential election for the entire nation.”

The win was potentially significant on several levels.

First, it’s Rubio’s first primary win, and provided the first tangible evidence that the stop-Trump candidate who is the choice of many GOP activists and Republican elected officials can translate that preference to a broader electorate. Previously, his only win had been in the Minnesota caucuses.

Second, it came at a time when Trump and Cruz had been openly calling for Rubio to get out of the race. Here, however, the lack of interest in Trump and Cruz was deep and widespread. The New York tycoon was a distant second with 13.6 percent of the vote, with Cruz receiving only 9 percent. Kasich, who had no real organization in Puerto Rico, finished fourth with 1.4 percent.

Third, Rubio’s commanding position here in the days leading up to Sunday’s vote afforded him the opportunity to focus on the one person he really wants to be running against: Hillary Clinton. Their sparring began here last September when Rubio and Clinton happened to be campaigning in Puerto Rico on the same day.

They got into it a little bit back then. Speaking at a packed restaurant in Santurce, Rubio delivered in Spanish his standard stump speech extolling his parents’ immigrant story—and adding a passionate pitch for Puerto Rican statehood, which is popular among the island’s Republicans. But he used Hillary Clinton’s native tongue—the only language she speaks—when criticizing her support for allowing the government here to declare bankruptcy.

“It sounds to me like Secretary Clinton’s plan for Puerto Rico is to continue the same projects that they’re doing now,” he said in response to a question asked in English. “The people who are rallying behind her today are the people who put Puerto Rico in this fiscal mess to begin with.”

Finally, and this is really all that matters, Rubio’s small victory here sets the table for a possible pivotal victory in his home state. The March 15 primary is delegate-rich Florida is winner-take-all. Rubio is believed to have a strong base of support among Miami’s Cuban-American community, and among GOP establishment voters in Florida. If he can run as well among the huge Puerto Rican populace that has relocated to the Sunshine State after fleeing the economic mess here, he could have a breakthrough moment.

Hillary Clinton alluded directly and lightheartedly to this factor when she visited the island in September. She noted how many Puerto Ricans have migrated to Central Florida—and how they have trended Democratic in the last two elections, to the benefit of Barack Obama. And she hinted with a smile that she wouldn’t mind a little of that love herself.

“It always struck me as so indefensible that you can’t vote for president if you live here,” she said. “But if you move to Florida, which of course, I’m just naming a state—you can vote for president.”

For his part, if Rubio doesn’t win Florida, where he still trails Trump in the polls, it’s difficult to see any way he can secure the nomination. Luis Fortuño, a popular former governor who worked hard for Rubio this month, admitted as much. Fortuño suggested to reporters here that if Rubio can win Florida and Kasich wins his home state of Ohio, the GOP could block Trump’s path, probably at a brokered convention.

“If for some reason there is one candidate who sweeps everything including Ohio and Florida,” he said, “the answer is no.”

The former governor was talking about Trump, but then again, so is everybody else. On this island, antipathy for Trump reached even behind prison bars. Puerto Rico is one of the handful of jurisdictions in this country that lets convicted felons vote; and here that right extends to those currently serving their sentences. The convicts apparently took their civic duty seriously—even if they, too, can only vote in presidential primaries, not general elections.

“This is a democracy … and Puerto Rico needs help,” 46-year-old inmate Edgardo Rodriguez told the Associated Press. “This [economic] crisis is choking us."

None of several inmates interviewed by the AP revealed their choice of candidate, but they weren’t shy about saying who they opposed. "Obviously, it was not for Donald Trump," Rodriguez said. "He hates Latinos."

With his eye also on Florida, Trump has been trying to tamp down that very perception. His campaign released a statement this week saying that the front-runner has visited this island many times and likes it very much—along with its residents.

“The best Puerto Rico has to offer,” the Trump statement said, “is its people.”

That was nicely put, but as far as Rubio is concerned—and as Hillary Clinton said herself—it’s even better for a candidate who is popular here if those Puerto Ricans happen to live and vote in Florida. Those voters could determine the direction of this campaign.