Noble, watched by England coach Steve McClaren, was overrun by City's midfield in the first half while Lee Bowyer, looking a shadow of the player he was with Charlton and Leeds, was substituted at half-time.
"There was just silence in the dressing room afterwards because we knew we hadn't performed," said Noble.
"It was such a big disappointment because everyone was looking forward to this season so much. We have to keep things in some kind of perspective though. It's only the first game of the season. Last season we won that and look what happened afterwards."