The father of a 10-year-old boy pulled from dangerous surf off the California coast says he will be “forever grateful” to the teenage lifeguard who risked his own life to save his son.

Video of the dramatic rescue at Seabright Beach in Santa Cruz has been viewed around the world after 16-year-old lifeguard Ryder Williams sprinted into pounding waves to reach Nathaniel Rai, who had been swept out by powerful surf.

“He ran into that water despite those conditions that are deadly,” Nathaniel’s father, Sumit Rai, said. “You have 10-foot waves, you have rip currents. It is not safe for him to go into that water. So he’s risking his own safety.”

Nathaniel was standing in shallow water last Saturday when a series of powerful waves suddenly dragged him into the ocean.

Rai was at his home in Dallas when he received the call every parent dreads.

“My son told me that he drowned,” Rai said. “My son told me that he went unconscious.”

He said Nathaniel was still in shock when they spoke.

By the following morning, Rai had watched the rescue video, which later drew attention from President Donald Trump.

Williams said he saw the boy lose his footing in ankle-deep water and immediately radioed for help before racing into the surf.

“After the first wave, I was unable to pull him out because he was limp and the waves were pushing so hard,” Williams said.

California State Parks said Nathaniel was swept about 15 yards offshore before Williams reached him. The rescue video shows the teenage lifeguard diving into crashing waves while holding the unconscious boy before another lifeguard and several bystanders helped bring them safely back to shore.

“I’m grateful to have had the opportunity to return the child to his family safely,” Williams said. “This is my job and I love what I do.”

Nathaniel was evaluated by medical staff and released without serious physical injuries. Rai said his son told him he coughed up sand after reaching shore but is now struggling with the emotional impact of the near-death experience.

“He’s still been thinking about it a lot. It’s on his mind,” Rai said. “It bothers him when he’s sleeping. So it’s obviously traumatizing.”

Rai has since contacted Williams in the hope of thanking him face to face.

“What he did, I can never ever repay,” he said. “I’m forever grateful.”