PHILADELPHIA — Sometime during the haze of his hectic 24 hours, when he learned that a dream he’d had since he was 7 would be fulfilled, Mets prospect Dominic Smith betrayed his scouting report.

Scouts have long raved about his soft hands at first base. But as he waited at the airport for the flight that would take him to his major-league debut, he dropped his cellphone.

The impact cracked the screen. For a while, the phone worked. Smith could hear the buzz of friends and family sending congratulatory texts. But he couldn’t read them.

“I’m sure that a million people are thinking I’m big-leaguing them,” Smith said Friday before debuting in the Mets’ 7-6 win over the Phillies.

Amed Rosario hit the first homer of his career, a solo shot that put the Mets ahead in the ninth. Earlier, Michael Conforto hit his 25th homer. Smith, 22, went 1-for-3 while playing first base and batting sixth.

“It still really hasn’t sunk in,” said Smith, whose nerves were revealed when he missed backhanding a routine grounder to first. But after striking out on three pitches in his first at-bat, he bounced a single up the middle in the fourth.

Smith was greeted at first base by coach Tom Goodwin, who took on the No. 88 in honor of childhood hero Lynn Swann so Smith could wear his No. 22.

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“To be here today, it’s just an amazing feeling,” Smith said.

“More than a teammate, I feel like he’s my brother,” Rosario said through a translator. “The same excitement he’s feeling, I’m feeling for him.”

Righthander Seth Lugo established a career high with eight strikeouts but allowed five runs in 5 1⁄3 innings, surrendering eight hits and walking four. His ERA jumped to 4.85.

The Mets fell behind 3-0 thanks to Lugo’s early struggles, crawled back to seize a 6-4 advantage, then allowed the Phillies to get back into it.

Yoenis Cespedes knocked in four runs, including a three-run homer. But the Phillies’ Cesar Hernandez hit a solo shot off Jerry Blevins to tie the score at 6 in the eighth.

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Rosario answered in the ninth. His homer came on a night in which he entered hitting .161 since his promotion on Aug. 1.

“Even though I’ve had a bad couple of days, this really helps my confidence,” Rosario said.

Smith’s night ended along with Lugo’s in the sixth inning. With the pitcher’s spot set to lead off the next frame, manager Terry Collins pulled the prospect as part of a double- switch. It came shortly after Smith failed to backhand Freddy Galvis’ grounder down the line.

The Mets have long been out of contention, and big-league debuts at this time of year are a matter of celebration. The timing was odd.

Still, it was an otherwise successful debut for Smith, a first-round pick in 2013 who is a central part of the Mets’ plans to contend in 2018. Along with Conforto and Rosario, who was promoted Aug. 1, Smith is part of a young nucleus. On Friday, the three spent time together in the clubhouse, just as they had at various points during their climb from the minor leagues.

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“I’m excited for him,” Conforto said of Smith. “I know he’s been waiting a long time for it.”

The looming promotion hadn’t been a secret. After the trade deadline, general manager Sandy Alderson hinted it would be close. So Smith was suspicious when he was summoned to his manager’s office at Triple-A Las Vegas on Thursday.

He was told it was to discuss repairing a part of the machine he uses to treat sleep apnea. Instead, he received the phone call that made his promotion official.

“I was just going through a mix of emotions,” said Smith, who had his mother and brother in attendance Friday night.

Smith’s promotion begins the process of answering a few critical questions about his bat and his fitness, both of which will shape his future. “He always uses all parts of the ballpark,” Collins said, describing Smith’s gap-to-gap prowess.

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Said Smith, “I think I am learning how to really use my legs to get the ball in the air. That has definitely helped me in that category.”

As for fitness, Smith said it will be a priority. By the end of last season, he carried 260 pounds on his 6-foot frame. He took off about 25 pounds in the offseason, though some of that has been regained.

In the minors, fast food is an ever-present temptation. In the big leagues, where teams employ their own chefs, healthier food will be much more accessible.

“Late after games, there’s not much open, especially in those smaller cities,” Smith said. “You are surrounded by fast food and that’s where the majority of your stops are. It definitely can be extremely difficult down there. Up here should be easier.”