Editor's note: This story has been updated.

U.S. Sen. Ted Cruz was set Sunday to collect no delegates in Puerto Rico as Marco Rubio swept the territorial primary in his second win of the GOP presidential race.

Rubio, Cruz's colleague in the U.S. Senate from Florida, won the under-the-radar contest with 71 percent of the vote, well above the threshold to take all 23 delegates at stake. With all precincts reporting, Cruz finished third with 9 percent and billionaire Donald Trump second with 13 percent. 

The outcome is unlikely to change the Texas senator's argument that he is the most viable alternative to Trump, especially after a round of contests Saturday in which Cruz beat expectations and emerged with the most delegates of the day. Rubio's Puerto Rico victory follows a first-place finish Tuesday in Minnesota. 

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Rubio was seen as somewhat of a favorite to win Puerto Rico, where polling was hard to find in the lead-up to the primary Sunday. All three of the territory's superdelegates had already endorsed Rubio, who spent part of Saturday campaigning there. 

One of those superdelegates, former Puerto Rico Gov. Luis Fortuño, was among the Rubio supporters Sunday hailing his win there as a positive sign heading into his home-state primary March 15. Cruz has promised to "vigorously" contest Florida, hoping to deny Rubio a victory that he could use to rationalize staying in the race. 

"Voters of Puerto Rican descent in Florida ought to follow the trend shown today in PR," Fortuño tweeted. "I urge all to support [Rubio] on March 15th!"

Cruz's campaign had made a point of building support in the five U.S. territories as part of a long-game strategy, sending surrogates to the islands for weeks at a time last year. Last week, the campaign announced leadership in each of the territories, tapping attorney Antonio Hernandez to chair its efforts in Puerto Rico.

Puerto Rico was the first of the five territories to make known its choice for the Republican nomination. Guam, where Cruz has the backing of the governor, holds its convention Saturday.

Residents of Puerto Rico and other territories can vote in primaries to elect party convention delegates, but not in general elections. The Constitution says only states can participate in the Electoral College system that comes into play in November.