City were unable to reach the FA Cup final after being overtaken by an Arsenal side led by Aubameyang. The Gabonese finished off the citizens with a double.
The Manchester United team defended the title they won last year against Watford, but this time they fell in the semi-finals.
"We didn't play well, we weren't prepared enough. We're human too. The rival played well and sometimes this happens," said Guardiola after the match.
He also had words of praise for the man who once was his own technical assistant: 'Arteta has created something special at Arsenal already', said the Spaniard, who no doubt was not expecting such a crushing loss.