The gap in class between these two old rivals was evident for all to see, as Pep Guardiola's men took a 12 point lead over the 'Red Devils'.
While Mourinho's team have improved in recent weeks, the performance showed that they still have a long way to go before they will be genuine title contenders.
Despite being a United fan himself, Gary Neville admits that his team has a way to go: "Even with the players he is bringing in, he is still stuck with the players from previous managers," the former Man Utd defender told 'Sky Sports'.
"It's a question for Jose Mourinho, where do Manchester United sit? And it's not a case of finding a final piece of the jigsaw and all of a sudden they are going to win the league because at the moment the jigsaw is half-empty.
"When you look at it you're not even sure what pieces are missing and that's something the board, the senior scouts and coaches have to sit down and work out.
"They finished second last season which was the best finish since Sir Alex Ferguson. It's so confusing watching Manchester United because you don't know what or who to change."