It is a far cry from Rooney's poor form of 12 months ago, with Ferguson believing the trigger has been his number one striker's new-found maturity.
"When players get to their mid-20s, there is more thought in their game," said Ferguson.
"Their timing is better. Wayne's presence is good and he is looking fantastic."
Rooney was joined on the scoresheet by strike partner Javier Hernandez.
Handed his first start of the season, the Mexican took just four minutes to open his account, nipping in front of Gary Cahill to touch home Nani's low cross.
Rooney then took centre stage, netting twice before the break and completing his three-timer after the interval before Hernandez rounded off another amazing win, coming just a fortnight after United scored eight against Arsenal.
"Hernandez's movement, speed, imagination and presence within the game was terrific," said Ferguson.
"He is a menace to any defender. Over the years the second season for players can be hard. But I never had any doubts."