In his book Saburo Sakai said that he followed a disabled American fighter at Guadalcanal. He said he flew near it and put a single cannon round into it’s engine.
The pilot bailed out.
I have no way of knowing if he was telling the truth or not.
I have the book, I think he had a conscience, and was very frank. He also meet with enemy pilots after the war. I believe if he lived by a code, then he may have spared an enemy pilot. He had the same compassion for a shot up enemy fighter plane.
many of the pilots of both nations failed to survive the war the 1st 4 months of pacific war.