NEW YORK — Downstairs at Trump Tower on Tuesday night, a couple hundred guests mingled and laughed over the blare of televisions delivering election night results as they staked out positions along the aisle Donald Trump would soon triumphantly walk down.

Upstairs in a much quieter bedroom, Trump watched the results with his wife and grown children. Analysts had called the Indiana Republican primary for him within minutes of the polls closing, but the past two months have taught Trump that winning states isn’t enough. Lately, his campaign has been hyper-focused on counting the heads of delegates. And then counting them again and again.

Then a tidbit of news popped up on social media that would end the head counting, obsessive strategizing and preparations for a contested convention that could get violent.

Sen. Ted Cruz (R-Tex.) — Trump’s former ally turned bitter rival — planned to drop out of the race.

“It was a shocking moment, it was incredible,” said Donald Trump Jr., Trump’s oldest son, who was in the room at the time. “We assumed everyone was going to be in it all the way until the end.”

Minutes later, Cruz was on television delivering a concession speech.

Downstairs in the pink-marbled lobby, a handful of Trump’s longest serving campaign staffers — those who believed in Trump back when few believed that the candidate would make it this far — gathered near a big-screen television to watch. They stood stoically, some with arms crossed or hands politely folded, and quietly listened to Cruz’s closing words as a bank of cameras recorded their every reaction. Corey Lewandowski, Trump’s embattled but faithful campaign manager, only occasionally looked up from his phone.

When Cruz said the words that made the news formal, the lobby burst into cheers. As Cruz said that the voters had chosen a path, one woman yelled: “Yes!” But the campaign staff remained quiet, so as not to be caught celebrating a rival's ultimate downfall. Two aides clapped. Lewandowski looked up from his phone and stared intently at the television, his eyes glistening. As the speech ended, he and a few other top aides embraced one another in a group hug that quickly became tighter and tighter, as if their grip communicated the screams of excitement that they couldn't yet yell.

They would likely no longer have to count delegates or strategize for the convention. They could now just skip ahead to the general election.

Soon, the Rolling Stones’ “Start Me Up” began to blare, a signal that the boss was about to arrive. Trump appeared dazed as he walked through a sea of his supporters with a subtle grin on his face. He was joined by his supermodel wife and his three oldest children, along with their spouses, who took their place around a lectern decorated with a blue sign reading: “Victory in Indiana.”

Trump pulled some notes out of his blazer and surveyed the dozens of reporters sitting before him. He started by recognizing his wife, children, late parents and siblings, then tried to summarize his feelings about everything.

“It’s been some unbelievable day and evening and year,” Trump said. “Never been through anything like this, but it’s a beautiful thing to watch and a beautiful thing to behold, and we’re going to make America great again.”

It took Trump more than eight minutes to mention Cruz. Instead, he walked through the timeline of his unexpected success. He marveled at the campaign's "tremendous victory" in Indiana despite nearly nonstop attack ads on television. And he thanked former Indiana basketball coach Bobby Knight for his endorsement.

Trump kept his bragging to a minimum and shared credit with his staff and supporters. He looked ahead to the upcoming contests in Nebraska and West Virginia. He focused on economic issues and promised to increase the number of jobs. It was as if he were giving the speech he had planned to give before he learned that the race had completely changed.

Finally, Trump got around to Cruz, calling him “one hell of a competitor” and declaring that the senator from Texas has “an amazing future.”

“I know how tough it is — it’s tough, it’s tough,” Trump said, his voice softer than usual. “I’ve had some moments where it was not looking so good, and it’s not a great feeling. And so I understand how Ted feels and Heidi and their whole beautiful family.”

Trump easily slid into the role of presumptive nominee. While a few Republicans announced they would rather vote for a Democrat than for him, many more announced that Trump had won them over. In his brief remarks on Wednesday night, Trump focused on the economy, party unity, creating jobs, national security and challenging Hillary Clinton. He promised to win over African American, Hispanic and female voters by promising to increase employment. He mostly skipped the gratuitous bragging and didn't plug any of his products. Mostly.

"This country — which is very, very divided in so many different ways — is going to become one beautiful, loving country," Trump said. "And we're going to love each other, we're going to cherish each other, we're going to take care of each other, and we're going to have great economic development."

As Trump continued to speak, his wife began to shift uncomfortably in her very high heels. His daughter Ivanka Trump grabbed the hand of her husband, who has been advising Trump. The audience snapped rounds of photos.

At the end, Trump didn't take a single question from reporters. Instead, someone hit play on the Rolling Stones, and he disappeared into the crowd.