It has been ruled that the second goal must go down as an own goal as the Mexican's shot was going wide of the goal before being deflected into the net by Ron Vlaar.
Hernandez came on as a half-time substitute and secured a 3-2 victory when grabbed the late header with just three minutes left on the clock.
After the full time whistle, Hernandez said: "I've seen the replay and I think it's going on target.
"The defender tried to get it away but I think he kicked it in the same direction as I shot."
Source: United Mad