A Manhattan woman was stalked by a pervy predator who snuck up behind her and exposed himself to her on a bustling Upper West Side street — proof, she said, “the city is getting worse and worse.”

“There were so many things that went through my head of what could have happened,” victim Adrienne Leon, 34, told The Post about her harrowing June 29 encounter. “It’s scary, because he’s still out there.”

Leon was waiting to pick up a meal at Tacombi, a popular  Mexican taqueria on Amsterdam near West 78th St., when she realized a stranger had followed her — and was fondling himself, just two yards behind her.

Making the matter all the more disturbing — the summer sun was still bright at 7:30 pm and there were plenty of people on the sidewalk, said Leon, who works in higher education.

“I noticed this man follow me from the corner of 78^th Street and Amsterdam, then when I moved away, he moved closer to me,” said Leon, who edged toward a nearby doorman building for safety.

The stranger, who was sporting a long beard, “was getting closer to me and looked as if he was fondling himself behind the mailbox across the building and he kept looking at me.”

Concerned, Leon walked just inside the entrance of the doorman building at 173 West 78^th Street, but felt someone behind her.

“As soon as I turned around, the man followed me into the doorway and was there with his penis in his hand and said to me, ‘Hey, I just want to talk to you, I think you’re beautiful,” she said.

“At that moment, I didn’t want to scream because I didn’t want him to hurt me with a gun or knife. I probably should have screamed, but I froze.”

Leon darted out of the doorway and into Tacombi, where she called 911.

The entire episode took less than three minutes but “it felt like an hour,” Leon said, adding, “It was so distressing and I didn’t know what was going to happen. The energy shifted. Was he going to attack me?”

“As I was on the phone with the 911 dispatcher, the same man approached another woman on West 79^th and Amsterdam and looked like he was harassing her, as her hand gestures kept saying ‘no,'” Leon said.

When police didn’t show up after 15 minutes, Leon, 34, went to the nearby 20th Precinct stationhouse to report the incident — only to emerge a short time later to find the fondler in the same area, walking block to block with his hands in his pants, stealing money from a homeless man’s cup, and looking into parked cars, she said.

Leon, who volunteers at Rikers Island teaching debate to inmates, recorded the reprobate but, “even with video evidence and a strong description, all I could do was file a complaint and hope the predator didn’t find another woman to do serious harm to,” she said.

After the terrifying encounter, the Los Angeles native, who has lived in the Big Apple for a decade, warned friends and family to be vigilant and voiced gratitude to the manager at Tacombi and the staff of the doorman building “for being concerned about my safety and situation.”

“After this incident I’m wondering whether I’m safer walking in the city or at Rikers Island,” she said, adding she’s “never had a negative experience” at the jail complex.

Brendan Sweeney, the doorman on-duty when Leon was accosted, said he saw the sleazy suspect “cornering women. I saw him approach her… I guess she was in the restaurant nearby and she came out and I was watching the camera, and I saw him acting weird so I kept watching to see what would happen and I saw the guy approach her… He was touching himself, looking into cars, taking change out of homeless peoples’ cups and mumbling to himself. This guy was really strange.”

Neighborhood residents vowed to remain alert in the aftermath of the ugly episode.

“You never know what creep could come up to you while walking home, so yeah, definitely staying alert and looking at your surroundings is super important,” said 26-year-old Emily, who declined to give her last name.

The NYPD confirmed the incident was reported but said no arrests had been made.

Serious crime in the 20th Precinct, which covers the Upper West Side, has gone up 30% so far this year compared to the same time period in 2021, according to NYPD data compiled through July 3.

Rapes are up 40%, from 5 to 7; robberies spiked 22%, from 49 to 60; grand larceny soared 28%, from 310 to 398; burglaries climbed 63%, from 46 to 75; and assaults skyrocketed 77%, from 30 to 53, the data show.

In August 2020, Upper West Side residents fumed that three neighborhood hotels housing hundreds of homeless men during the coronavirus pandemic had turned the area into a spectacle of public urination, catcalling and open drug use.

Additional reporting by Maddie Panzer