James McAtee hit a hat-trick, with Jeremy Doku scoring a brace. Also on the scoresheet were Jack Grealish (penalty), Nico O'Rielly and Divin Mubama.
Robinson later said: "You always know you're at the mercy of the quality of the competition. Man City and Pep have never disrespected anybody and tonight they showed us why they are what they are and why he is who he is. It's about dusting ourselves off, we've come on so much in 12 months and to be where we are in the league.
"We have one goal and that is to get out of this league. This is a glimmer of what we want to be and we know we've got so much to improve and we know where we want to be.
"I said to the players I would have taken eight goals conceded in seven games, I just didn't expect them to all come in one. We're proud of them, I really am. They never let me down. We make human error but that's part of the level we're at. Some of the things we weren't so good at, we'll make sure we're better. We'll learn because of today.
"For me, it's not a case of me trying to pick them up or have a go at them. You take it in the chin. You hope for these glamour ties and we managed to get it. This was never a game we would look at and use as a disappointment moving forward. We make sure we plan properly for our next game."