He was diagnosed with Lemierre's Syndrome, a rare (sometimes fatal) bacterial infection that was attacking his liver, kidney and heart. Eric was on life support for eight days - and Sock who was at home due to an injury - was by his side.
After that Sock has found a new tennis groove, lifting the trophy in Houston last year, reaching another final in Stockholm and compiling a 35-18 win loss record for the year.
He showed his powers of recovery today, coming back from an awful start to trump world No12 Kevin Anderson 1-6, 6-4, 6-4 in 98 minutes.
"He came out firing, didn't miss many first serves," reflected Sock. "From the ground he was playing really well but I was able to get a rhythm at the end."
The 23-year-old also showed his lighter side on court, tossing one of his socks to a surprised fan at the end of a match, a gesture he hopes might become his trademark.
"I'm trying it out for a bit to see how people react," said Sock. "A few guys have their signature things. I thought with such a unique last name it might be something clever and fun."
But Sock will need to be all business tomorrow, looking for just his second win over a top 10 player in 16 attempts.
"I'll have to be the aggressor, dictating points," he said. "If not [Ferrer] is very good at getting balls back, and making a lot of balls."