Sean McVay is finally coming clean on why the Rams were so bad against the Patriots in the Super Bowl last February ... saying he straight-up "over-prepared" for the big game.
Remember, Los Angeles came into SB LIII as one of the most potent offenses EVER ... but threw up just 3 points against Bill Belichick's boys in an epic loss.
Now, after reflecting on the sorry performance for 3 months ... McVay told Sports Illustrated he finally has the answer as to why it happened .