PHILADELPHIA, PA – There is nothing sweeter than revenge. And that is what the “Goretti girls” of St. Maria Goretti High School in South Philadelphia got yesterday when they chased down and beat up a man who allegedly had exposed himself to the students for the last month.

Police and neighborhood residents said between 20 and 30 girls, all dressed in their uniforms, dropped their book bags and jumped in after the man allegedly began to expose himself again. Onlookers and neighbors cheered the girls on and shouted “Pervert!” at the man.

After police arrived at the scene minutes later – shortly after noon – the man was taken into custody and driven to St. Agnes Medical Center, where he was treated for an injury to his mouth.

Police expected to charge the 25-year-old South Philadelphia man with multiple counts of harassment, stalking, indecent exposure, and corrupting the morals of a minor in connection with seven incidents.

The first encounter was Sept. 14. Police said 13 students were victimized, some more than once.

The latest encounter took place yesterday, when the man exposed himself to two girls walking in the 2000 block of South 10th Street, police said. It happened shortly after the school’s 12:15 p.m. early dismissal.

Except this time, police said, some of the girls and people from the neighborhood counterattacked. At one point, police said, the man broke free and tried to run.

Robert “Bobby” Lemons, who owns Rose’s Food Market at 10th and McKean Streets, was one of two men who caught the man.

“I was bringing the countertop up from my basement, and I saw him in the street acting really funny,” Lemons said. “He was rubbing himself, but he wasn’t exposed yet.”

Lemons said the man was up the street by a parked van, gesturing as if he were urinating, but then exposed himself to two girls after they passed by. Lemons walked across the street to tell a friend. They split up on both sides of the street and chased the man, tackling him in the middle of the block.

“Everybody was saying, ‘Don’t hit him, Bobby, don’t hit him,’ so I didn’t,” Lemons said. But while he was holding the man down, “the girls came and started kicking him and punching him, so I wasn’t going to stop them,” he said.

Lemons said the man tried to pull a knife from his pocket.

Kelly Simone, 15, was the first girl to get in a lick on the man. Simone, a sophomore at Goretti, recognized the man from sketches posted around school. Her friend was one of the girls to whom the man allegedly exposed himself yesterday.

“I looked down the street, and Bobby had the… man on the ground,” Kelly said. “I went up to him, and he started grabbing at my feet, so I kicked him. All the girls were scared to touch him, but I said: ‘Let’s show him what we can do.’ ”

Thomas Simone, Kelly’s father, said he was proud of his daughter and her classmates.

“They beat the crap out of him,” he said, laughing.

“I’m glad they did it for themselves and that they didn’t let this guy go,” Thomas Simone said.

“You know what’s funny? They got their own revenge. The girls got him without the police.”