With the concession of his closest rival, Donald Trump on Tuesday night capped an improbable — and many thought impossible — run to become the presumptive Republican nominee for president.

Trump crushed Ted Cruz in the Hoosier State with more than 50 percent of the vote in a three-man race, forcing the Texas senator to admit he had no chance to win the nomination and quit his campaign.

The mogul won at least 51 of 57 delegates in Indiana, giving him 1,047 and a clear path to the 1,237 needed for the GOP’s nod.

It’s a triumph for a Trump candidacy that just 11 months ago seemed as unlikely as any reality-show plot line, when the New York real estate developer threw his hat into the ring and pundits, Republican insiders and late-night comics immediately wrote him off.

‘I’ve said that I would continue on as long as there was a viable path to victory. Tonight, I’m sorry to say it appears that path has been closed.’ - Ted Cruz

He didn’t have the typical presidential pedigree: a billionaire playboy who was as famous for his tabloid-fodder lifestyle as for his business dealings.

He was brash, brazen and the star of the reality TV show “The Apprentice.”

But after years of mulling a White House run — and becoming one of President Obama’s biggest critics — he slowly built a base that helped catapult him to the center of the race almost as soon as he descended the Trump Tower escalator to make his announcement in June.

His grandiose proposals to build a wall along the US-Mexico border, fight a trade battle with the Chinese, and ban all Muslims from entering the country were predicted to sink his nomination — but actually proved popular with working-class voters, especially those in Middle America, who are worried about jobs and terrorism.

He made controversial comments about women and Mexicans that experts said would have doomed any other candidate, but his legions of fans, who filled rallies by the tens of thousands, loved his “political incorrectness,” and his poll numbers soared.

Trump now turns toward the general election, where an all-but-certain match-up with Democratic former Secretary of State Hillary Clinton will play out.

The election battle will be unusual, not just for the high profile of both parties’ candidates, but because each has some of the highest negative ratings ever.

In a victory speech before a packed house at Trump Tower after the Indiana primary, the magnate graciously lauded Cruz for dropping out of the race, and called for the party to come together to defeat Clinton.

“I didn’t expect this. I didn’t expect it, and what Ted did is really a brave thing to do and great thing to do because we want to bring unity to the Republican Party,” Trump told the crowd.

He then turned his attention to the former first lady, vowing, “We’re going after Hillary Clinton.”

Trump also touted a Monday Rasmussen poll that gave him a 2-point lead over Clinton in the general election, before returning to his familiar campaign themes of job creation, border security and a strong military.

Cruz, speaking earlier to a half-empty ballroom at the Indianapolis Crowne Plaza hotel, admitted he had no chance after his devastating loss.

“From the beginning, I’ve said that I would continue on as long as there was a viable path to victory. Tonight, I’m sorry to say it appears that path has been closed,” Cruz said, as Trump’s supporters who had gathered in New York to hear their man cheered the televised remarks.

Minutes later, Republican National Committee Chair Reince Priebus tweeted:

“@realDonaldTrump will be presumtive [sic] @GOP nominee, we all need to unite and focus on defeating @HillaryClinton #NeverClinton.”

CNN political director David Chalian said voters’ worries about the economy handed Trump his impressive win.

“This is a big victory among a huge swath of voters. His message is working,” Chalian said.

Trump’s margin was so large that Fox News and other networks declared him the winner just moments after the polls closed in part of the Hoosier State at 7 p.m. New York time.

Trump took to Twitter minutes later.

“Thank you Indiana, we were just projected to be the winner. We have won in every category. You are very special people-I will never forget!” he wrote.

With 97 percent of the vote in, Trump had a 17-point lead over Cruz and a 46-point advantage over John Kasich.

But a rep for Kasich said the Ohio governor would continue his long-shot fight for the nomination until the end.