Di Matteo refused to deflect responsibility for the 3-0 loss in Turin - the club's heaviest ever in a group match - as the biggest selection gamble of his reign backfired spectacularly.
He said: "I'm responsible for the result. I'm responsible for the performance. It's a negative evening for us.
"If anyone has to take the blame, it's me. I selected a team I was convinced was the right team to win against Juventus, or get at least a draw, so the blame belongs to me."
He added: "I'm responsible for positive and negative results. This is what I do."