Ronaldo: Espanyol were tough
The Samba star had previously gone two games without a goal, and even managed to score one with his head.
"My headed goal was rare," Ronaldo said. "It's a part of my game which I've worked on a lot recently, but doesn't seem to be getting any better.
"I still have a lot of work to do in that department."
Ronaldo, who had never previously scored against the side from Barcelona, was critical of Espanyol coach Javier Clemente's defensive tactics.
"I've finally managed to score a goal against Espanyol," he added. "It is not easy scoring goals against teams who come solely to defend.
"Espanyol played with five defenders and four midfielders and it was difficult finding any space," he concluded.