Cole tested his defensive abilities on a number of occasions against Ronaldo, for Chelsea and England, and he showed the winger an imaginary pocket in his shorts at Old Trafford.
"I miss playing against Cristiano Ronaldo, I really do," he said in the News of the World.
"Manchester United don't seem the same without him - he's the best player in the world.
"I used to love our battles. If I'm concentrating, on my day I can do well against anyone, but he was something else.
"I love his skills, but I nearly ripped my groin when I was first playing against him because he did a trick and I did the splits.
"My mates were killing me after and I thought, 'Right, he's never embarrassing me again'.
"A couple of years later at Chelsea I showed him the imaginary pocket in my shorts and their fans were lapping up the banter."