The boy was on a trip to the Skyline Pool at 138-52 Elder Ave., near Kissena Boulevard, with his day camp when he somehow drifted from the shallow end of the pool into the 5-foot-deep section, witnesses said.
Someone by the public pool noticed the boy struggling and told Will Rivas, the lifeguard on duty, who sprang into action.
''This guy said to me, 'Will, there's something in the water,'" said Rivas, 18, a recent Holy Cross High School grad who is college-bound. "I saw it was a kid. I jumped in and pulled him out. He was unconscious."
When he pulled the boy from the water, his face was blue, so Rivas, of Flushing, began performing CPR with the help of another lifeguard.
A witness at the scene said the boy didn't immediately respond to the lifeguards' efforts, but he took a turn for the better at some point.
"After about 20 seconds, he twitched and his eyes moved," said Ted Jackson, 73. "He coughed up some bile and was making little movements.''
EMTs arrived on the scene soon after, and the boy was taken to New York Hospital Queens, where he was in fair condition.
Jackson, who has been going to the Skyline Pool for 40 years, said the young lifeguard may have saved the boy's life.
"He gave a very appropriate reaction," Jackson said of Rivas. "They were doing their jobs with speed and professionalism.''
Rivas has pulled people from the water before, but this was the most challenging rescue by far, he said.
''I was confident in my training," Rivas said, who has been a lifeguard for two summers. "But this was scary. He looked like he was gone.'