Ronaldo, who realised a dream when his world record £80 million move to the Spanish giants was sanctioned by Manchester United in the summer, scored in the 2-0 win over Villarreal on Wednesday night.
Ronaldo took less than a minute to break the deadlock in Sunday's 5-0 defeat of Xerez, and he needed just a few seconds longer to repeat the feat as Manuel Pellegrini enjoyed a winning return against his former club.