Ferguson also reserved words of praise for the returning Paul Scholes, who scored the opening goal of the match.
"It was a good score line. I thought we could have scored more in the first half in particular. We had a lot of great chances," Ferguson told Sky Sports News.
He said of Scholes: "At his age, and the fact he has just come back, we were looking for him to control centre midfield, which he did, but he had the instinct."
"I think so, but these inconsistencies are confusing to everyone. The referees need to be given direction."
United continue their league campaign away to Arsenal next Sunday.