The 3-1 defeat at Watford on Sunday means the Red Devils have lost three games on the spin.
Murphy told the BBC: "(Jose) Mourinho will be massively disappointed to have lost three games on the spin - it is just not something he does, especially with a performance like that one.
"But it should not be panic stations at Old Trafford, because there is plenty of quality and talent in their squad, and lots of options in every department.
"Mourinho just needs to find a better balance with his team in games like this where they have most of the possession, and make sure they are more creative, because they were a bit predictable against the Hornets.
"Like any manager who goes to a new club, Mourinho has brought in his own players but he also has to look at the ones who were already there, and work out which ones suit the way he wants to play. That is going to take time.
"It just so happens that City have hit the ground running while United have had this little wobble, but it is a long season and everyone is going to have a bad spell at some point - even City."