DAVE Furukawa is mourning the loss of his beloved guide dog, which died while saving the man's son in Atlanta.

Furukawa, who is visually impaired, was at intersection with his son, Will, and guide dog, Simon, when a car ran a nearby stop sign, according to NBC 11 Alive news.

Bystanders said the car struck Simon, then Dave. That's when the badly-injured boxer's protective instinct kicked in.

"What people have said is that Simon either got up or jumped out, and pushed my son out of the path of the car," Furukawa said.

Witnesses carried Will down the street to his mother, with Simon following.

"Broken leg, gash on his side and internal bleeding, but he followed home," said Furukawa. "Once he was sure Will was okay, he laid down.

"This is true loyalty and courage."

Dave says Simon died on the way to an emergency vet clinic.