Indeed City played a great game but they need De Bruyne back as quick as they can if they want to go back 2 back UCL champions. This season is way hard for them to conquer the trophy and from my point of view , I do think Bayern are the 1st favorites and then City and Real but you are right , De Bruyne presence will be felt as soon as he steps on the pitch and City also needs him for EPL fight. 
Manchester City really need his presence in the squad to help improve their attack. The Cityzen had lost their best momentum since losing De Bruyne, they had slipped several times in the EPL which made them lose the top of the standings. Manchester City still has a big chance to win the UCL trophy in a row, they must be able to return to their best playing form like last season to compete with Bayern Munich and Real Madrid who appear consistently in different competitions. De Bruyne's presence will create a different atmosphere in the squad, he is expected to make a contribution that can improve the quality of Manchester City's game.It seems this is going to be another interesting thing for sure. As long as city will able to play with its full squad and i do believe if manchester city will able to play perfectly against any opponents. Many people are still waiting for the superstars to come back.
Im very convincing if manchester city will able to win the trophy again. Im feeling much better once i have seen that if key players of manchester city will be playing. It's caused by that if i just think that if those are still performing so well even though they have suffered injury
I have no complaint about that at all caused by they will always help city to win any trophy till this time. Manchester city is consistently winning the trophy.