Fernandes was at fault for Leicester's first goal as they held United to a 2-2 on Saturday, having scored and assisted already to put the Red Devils in a commanding position.
The Portuguese was caught in his own half during the first period - being dispossessed in the build-up to Harvey Barnes' equaliser.
And despite his efforts in attack, Hargreaves admits that gifting such an easy goal would have seen Fernandes in deep hot water if Ferguson was still in charge, though he says that Ole Gunnar Solskjaer is likely to go easier on his star man.
“Fernandes, sometimes as good as you are, don't play with risk in your own half," Hargreaves told Premier League Productions.
“He's fortunate Ole is a nice manager because I can only imagine what Sir Alex would have said to one of us if we tried to nutmeg someone in our own half."
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