As they say, football is hard to predict. Let the Manchester United players and fans get over their heartbreak and not let the defeat demoralize them due to their points in the Premier League, they still have a good chance of finishing among the top 4 contenders.
Of course, their chances of finishing in the top four is quite strong, they even have a faint claim on the EPL title. IIRC, two weeks back some people were already calling it a three horse race, so i don't think so much has changed, though personally i don't think it is possible for Manchester United to win the EPL title this season, imo the race is between City and the Gunners.
Having said that, it was indeed a heavy defeat, and quite embarrassing, but the truth is that it was only 3 points lost, so they have to forget about that defeat and move forward, dwelling on it would just cause further losses in the future. Liverpool on the other hand are slowly coming back into the top four picture, it would be interesting to see how things pan out.