The Portuguese forward is set to face his old club when Real Madrid host the Red Devils in the last-16 first leg clash at the Santiago Bernabeu on Wednesday night.
Tomorrow will represent Ronaldo's first meeting with his former employers since leaving Old Trafford for Spain in 2009, with Sir Alex Ferguson having already identified the 28-year-old as the biggest threat to Manchester United's hopes of progressing to the quarter-finals.
Real Madrid boss Jose Mourinho has already described the fixture as the match the world wants to see, but Ronaldo insists he would have preferred to line-up against the Premier League giants in May's Wembley final.
Ronaldo will be looking to add to his incredible goalscoring record - which has seen him find the net 182 times in 179 appearances for the Primera Division club - when he lines up against Manchester United later this week.
Often players keep celebrations to a minimum when notching against a former club, but the FIFA Ballon d'Or runner-up admits he does not know what will happen if he puts one past United. But, either way he's looking forward to returning to Old Trafford.
"If I score against them it would be spectacular, of course. It would be a beautiful sensation, but if I score, I can't say what I'll do.
"It would be something spontaneous, but I'd love to be in that situation. I'm sure the United fans would receive me well."