Danny Welbeck scored a vital away goal for United at the Santiago Bernabeu before Cristiano Ronaldo levelled against his former club in the first leg of their last-16 encounter.
"We now have the advantage," Rafael told Globo Esporte. "It's like it is still goalless and we have the home leg to come, but I still think we could have won the game. We now have a great chance of advancing to the next round."
United welcome Madrid to Old Trafford for the return leg on March 5.