A Brooklyn man once slashed by the on-the-lam suspect in a fatal weekend crime spree told The Post on Monday he’s shocked the “punk” is still free — and wants to take a crack at him.

“I’m mad. I’m upset,” said Isaac Alvarez, who was randomly knifed in 2020 by Joevani Vale, the suspect in Saturday’s fatal stabbing of an 83-year-old man and separate attacks on two women minutes earlier in Boerum Hill.

“If I was to see him, I would go at him,” Alvarez said of Vale, 26.

“I still wanted to react that day,” Alvarez said of his own violent encounter with Vale. “And now especially that he killed somebody. He’s a punk.”

Vale is still being sought by cops for allegedly slugging a woman, slashing another lady and then killing elderly Ramon Cintron in the elevator of the Wyckoff Houses public-housing complex during a bloody one-hour spree early Saturday afternoon.

Cintron, a beloved local fixture, was killed after hitting the lottery numbers at a local deli and being followed home, neighbors told The Post on Sunday.

Vale, who has at least three previous busts on his rap sheet, lives in the same building as Cintron, police said.

Vale was arrested for public lewdness in 2015 and on a forcible-touching charge in 2016, both in Brooklyn, law-enforcement sources said.

His most recent bust came after he slashed Alvarez in Park Slope in the borough on Sept. 20, 2020.

“I didn’t even know I got stabbed,” Alvarez said Monday. “He was walking one way, and I was walking the other way. He’s coming towards me, and my arm was up because I was on the phone. I was trying to move to the right, and once I got close, he bumped me real quick.

“My reflexes caused me to push him off,” he said. “I looked at his hand, and I see he has a knife. He just kept saying, ‘What? What?’ I had to keep my hands up to guard myself. Once he realized I wasn’t backing off, he jogged away.

“I didn’t pay it no mind, but then someone in the car that saw the incident said, ‘Yo, you’re bleeding.’ I touched my back, and I felt a whole bunch of blood,” Alvarez added. “I had no idea.”

He said his cousin drove around the neighborhood and snapped a photo of Vale nearby.

Vale was arrested and ordered to undergo a psychiatric evaluation, according to the Brooklyn District Attorney’s Office on Monday. He pleaded guilty to felony and misdemeanor assault as part of a deal in the case that required him to undergo a 13-month mental-health program or face three years in prison.

He successfully completed the program in April 2022, prosecutors said.

On Saturday, Vale allegedly slugged a 47-year-old woman around 1 p.m., then slashed a 31-year-old lady before he allegedly followed Cintron into the elevator and unexpectedly stabbed him in the neck.

Surveillance video allegedly shows that Vale then kicked the elderly victim and ran off, according to cops and video.

Additional reporting by Larry Celona