Sir Alex said before he retired in May that United had rejected a transfer request from Rooney, who was the subject of two failed bids from Chelsea during the summer.
But Ferguson, who is now a director at Old Trafford, is pleased with the England forward's recent displays for the Red Devils.
"Wayne was fantastic [against Bayer Leverkusen]. I'm pleased to see that," he told MUTV.
"He's got his energy back, the determination, his purpose to attack. As a director, I'm delighted to see him back to what we always remember him."
Rooney was keen on a move away from United during the summer after being left "angry and confused" over his situation at the club, but new manager David Moyes managed to keep hold of the 27-year-old.
Ferguson added: "With [Robin] van Persie and Rooney, there are forwards that can win games and [Antonio] Valencia's back to his best."