The Portuguese manager declared Celtic the better side as he watched his team fall behind after seven minutes before wilting in front of their rampant city rivals.
“It is not a question about being disappointed,” he told Sky Sports, “it’s more a question of being realistic. So after a 5-1 defeat you don’t have much to say. They were better, they deserved to win and that’s the history of the game.
“We really believed that the players and the team were doing what we work along the season, along the week but it just took five minutes and everything changed.”
Caixinha took full responsibility for the result and was clear that improvements have to be made.
“The only guilty (person) here and the main responsibly is me,” he said. “The players did everything they were ready to do so I assume all the responsibility about this result and this performance.
“When I say I take responsibility I take responsibility for everything, I don’t need to say it was about this or about that.
He added: “We need to short that distance and we need to work stronger in that direction. It’s not only a question of money it’s a question of getting the right choices. I’m always optimistic.”