#3 Refusal to act quickly
Keeping in mind the home-leg of the Champions League quarterfinal against Liverpool later this week, Guardiola’s decision to keep Kevin de Bruyne, Sergio Aguero, and Gabriel Jesus on the bench against United was understandable.
However, what was not understandable was his unwillingness to throw them into the mix as soon as things started to turn bleak in the second half. All three players came onto the pitch after Chris Smalling had volleyed the Men in Red to take the lead. Such decision making is not what you would expect from a manager as proactive as Guardiola.
The City defense could not tighten things up after the first goal of the night. In fact, they seemed to unravel further with every attack the visitors made on their post. The weakness that they harbour at the back, which has been on display at times this season, cost them the goals, the match, and the chance to clinch the title against their arch rivals.