Mike Krzyzewski Shuts Down Unretirement Rumors, 'Done With Coaching'

Mike Krzyzewski is riding off into the sunset for real -- the Duke legend is shutting down any speculation he might return for one more season ... saying he's "done with coaching."

The Blue Devils' head coach of 42 years confirmed he is, in fact, retiring for good in an interview with ESPN U on Tuesday ... just one day after his former player, Jay Williams, stated he could see Coach K return in 2023 after key assistant Nolan Smith left for Louisville.

When Coach K was asked if he was going to "pull a Tom Brady" and come back ... he says it ain't happening, but went on to say he's flattered by the comparison to the 7-time Super Bowl champ.

"Wow, to even be put in the same room, maybe, that…