D.C. wasn't in the best shape to talk after his loss to Jones at UFC 214 and left the Octagon after only a brief statement with Joe Rogan.

But now, he's opening up ... and giving props to his biggest rival.

"Congratulations to Jon Jones and his team. They did a phenomenal job and got the victory."

Cormier also apologized to ref Big John McCarthy -- who called the fight in the 3rd round while Cormier was taking a flurry of uncontested shots to the head from Jones after a big head kick.

D.C. got into it with McCarthy after the stoppage in an emotional reaction to the loss.

"To Big John McCarthy, I would like to apologize for acting up with you. I am thankful for the time you gave me to try and defend myself and stay in the fight."