"I didn't know if I was going to play [the semifinal]," said Sock. "I woke up sweating through my sheets and wasn't feeling great at all this morning. I woke up, had some food, then went back to sleep for about four hours. Then I warmed up about 30 minutes before my match - so not the ideal schedule."
Sock has "some kind of virus" and looked distinctly pale in the after-match press conference last night, after reporting that he felt "all right" during the time on court.
So will he be OK for today's final?
"Not sure, I'll see how I feel in the morning," said Sock. "Hopefully [I can get] that little window when I am on the court [and] feel good again."
The Nebraska native was touch and go to play before yesterday's match, with the magnitude of the occasion swaying his decision.
"I was really hoping I could play and didn't want to have to pull the plug in an ATP semi," said Sock. "Maybe if it was first round, ahead of next week, I might consider it a little more."
The result also meant that Ferrer has to postpone his tilt at history, aiming to become the first player to win five titles in Auckland.
The Spaniard was obviously cut up at the defeat, and left the venue a few minutes after his loss, skipping his usual warm down routine and doing his press conference via phone from his hotel.
In a brief interview, he admitted he was "very sad" at the loss but paid tribute to the "surprising" performance from Sock.
The world No 8 had started well, grabbing a break in the sixth game of the first set and hanging on with relative ease.
During the break between sets, Sock called for the ATP doctor to discuss his condition.
He then changed his shirt, and changed the match. The world
No 25 streaked to a 4-0 lead, and won 12 of the next 15 games. Ferrer continued to hustle but couldn't make any inroads.
Sock had all the momentum, but still showed his sportsmanship when he overruled the umpire to call a Ferrer serve in during the third set.
