Ronaldo opened the scoring, sliding the ball between David James' legs with ease after a neat passing move, with countryman Nani setting him through.
He scored a second soon after as not even 15 minutes had yet been played. He struck an incredible free kick from over 30 yards out with incredible precision as it rocketed into the top corner, with David James left rooted to his spot and the Pompey players absolutely speechless.
It was without doubt a genuine contender for goal of the season - and Ronaldo acknowledges it is one of his best.
"I've seen the replay and it is difficult. Maybe it's the best, maybe, I don't know. It's difficult to say," he pondered.
Describing his unique technique, which provides incredible power without requiring much dip or swerve to hit the back of the net, he was jubilant without being too descriptive: "This is my style. I feel great, so when I shoot like that, sometimes it is a goal, sometimes not.
"I'm very happy and proud to help my team."
Ronaldo has now scored an absolutely phenomenal 27 goals in 29 appearances so far this season, and he does not look like stopping any time soon.