Yesterday's win over Sunderland was the day the club renamed the towering North Stand after Ferguson and announced a statue will be unveiled at Old Trafford in his honour next summer.
Ronaldo said: "I wanted to go to the party. It was amazing for Sir Alex. He's had such an amazing career and he keeps going. Because of our training schedules I couldn't make it. That's why I was desperate to speak to him on the phone.
"Unfortunately I couldn't get through so I told chief executive David Gill to pass on my congratulations for all Sir Alex has achieved. He is a fantastic manager. He helped me so much in my career."