A Good Samaritan and lifeguards saved the life of a 5-year-old boy who nearly drowned in a city pool at a Brooklyn park Sunday.

A nearby swimmer saw the boy facedown in the pool at McCarren Park around 7:10 p.m. and jumped into action before the lifeguards on duty reacted, according to the quick-thinking man and a witness.

“I was swimming with my sister in the pool and I saw the little boy slumped over in the water and I yelled for someone to come over,” Anthony Torres, 36, said.

Torres, of Long Island City, said no one was making an effort to jump in after the child who “was submerged and slumped over, face down.”

Pool-goers were staring and pointing in shock as he yelled out for help and the Parks Department lifeguards weren’t acting quick enough, Torres said, so he sprang into action himself.

Torres, who was a lifeguard himself for two years, dove down and grabbed the boy.

“I had him on my forearms,” he said. “He was discharging water and vomit. I got to the edge of the [pool] deck and I put him on the deck.”

Torres said he turned the boy over so he could spit up pool water and at that point, two lifeguards came over to do CPR.

“He was breathing, his eyes were open but he was non-responsive,” he said of the scary moment. “I tried to pick his hands up but he was lifeless.”

The guards performed CPR on the child for about three minutes and were able to resuscitate him.

“They did CPR for like three minutes and he came to,” he said.

EMS rushed the child, who was conscious and alert, to Woodhull Hospital. He is expected to recover.

A witness also credited Torres with taking the vital first step to save the boy.

“We saw a guy carrying a kid to the side,” Dan Wiley, 59, said. “He picked him up carried him to the side and one of the lifeguards came down and did CPR immediately.”

Wiley said the lifeguards were using precious time arguing about what they should do instead of leaping into action.

“[The lifeguards] weren’t doing anything for a while,” he said. “There was arguing about what to do… and the guy that carried the kid and a lot of people were yelling about what to do.”

However, he credited the guard who successfully administered CPR.

“One lifeguard just jumped immediately and stayed doing CPR,” Wiley said.

After the near-drowning, the Parks Department and the NYPD closed down the pool — which was scheduled to remain open until 8 p.m. due to the ongoing heat wave — to investigate the incident.

Temperatures skyrocketed to 94 degrees Sunday amid an ongoing heat advisory — sending many New Yorkers to city pools and beaches to dip into the water for some relief.

The incident came as New York City — like much of the country’s coast — is dealing with a lifeguard shortage that has forced city officials to prohibit swimming in sections of beaches and cut pool programming. The city has increased the starting wages for parks department lifeguards in an effort to attract more to the job.

Torres said he never experienced such a harrowing incident as the child’s close call on Sunday.

“It [was] dramatic,” he said. “I was a lifeguard for two years and never seen anything like this.”