Pep Guardiola was the manager of one of the best teams in the history of football initially, so to beat them, apart from a top drawer-no nonsense performance, you also needed not just a bit, but a lot of luck as well.
At Bayern Munchen, the team at his disposal still had an incredible amount talent was one of the top 3 teams in Europe. His players, especially his defenders and GK, were suited to the system and the type of Football that he liked to play. But still a few glitches were visible in Europe, and Real Madrid, Barcelona and Atletico Madrid, all exploited them during his time in-charge at Bayern. This is a good read as to his failure at Bayern to win the Champions League.
http://www.foxsports.com/soccer/sto...ola-era-at-bayern-munich-was-a-failure-050416
Now at Manchester City, to be frank, Guardiola looks at have swollen something he won't be able to digest. City are not looking comfortable, have not won any game with as much vigour as they would've liked, but that might also be down to the fact that the manager is new. But still, there is something about his body language that seems a bit questionable to me. Tactically if Jose gets his men right, I don't see us dropping points in this game. City have been playing a 4-3-3 cum 4-1-4-1, with the attack minded KdB and Silva playing in the middle of the park and the Full Backs coming inside to cover for them. If Aguero is suspended for the game, I think we'll see Kelechi given a start, which will give them a physically imposing figure in the box. The big difference, I think, will be the dropping of one of KdB/Silva/Nolito for Fernando, for a greater defensive cover.
United should try to exploit their lack of young legs down their full back positions. We have fast players in Martial and Mkhitaryan who can give their FBs a huge problem if they get going. Curbing Silva and Sterling's partnership will be important, because they have been linking rather well this season and might pose a problem for Fellaini. This brings me to our midfield. Pogba tends to leave a lot of space for Fellaini to cover, so we might not see Luke Shaw advancing as much as we'd like (this could be seen in the Hull game as well).
All in all, I give United the edge in this one and if we our able to capitalise on Pep's inexperience in the league and their frailties, 3 points should be ours.