Lethargic, slow to react and shambolic in defence, Real fell behind to a seventh minute Costinha goal in their Group F Champions League encounter.
Yet at the end they were emphatic and deserved 3-1 winners of a lively Iberian derby thanks to goals from Ivan Helguera, Santiago Solari and Zinedine Zidane.
"It's always hard when you are losing at the start, but we knew the team was well prepared and confident. Porto are difficult, especially in dead-ball situations," said Real's Portuguese coach Carlos Queiroz.
"But I think we then began to control the game bit by bit, to play the way we can, play an attacking game, winning possession and controlling the pace of the game.
"I think we have got a fair result against a side which is always hard to beat." Queiroz said Real had learnt some lessons from the 2-0 defeat at Valencia.
"You have to talk things over. Real Madrid is a club with great expectations and high hopes, but is not invincible. We deserved to lose against Valencia, they were better than us and above all we made mistakes.
"All week we have been trying to correct those mistakes so that we could win here, win well and get a victory that will help us have a calmer group phase in the Champions League.
"I think it was a normal game, which we dominated in every way. We deserved to win, but I also congratulate the Porto players because they made us work for it."
BETTER START
Porto coach Jose Mourinho was left to reflect on what might have been after his team made the far better start.
"We were much better in the first half hour, I even think we gave the false impression that we are better than they, and we're not," he said.
"We were winning 1-0, Casillas made a great save, which could have put us 2-0 up and they couldn't even get through the midfield.
"Suddenly, I think their first goal was down to a defensive mistake of ours, with Helguera moving into an unmarked space. My only criticism of my team is that after conceding the goal that levelled the score, they didn't manage to be stable, solid or mature enough to carry on the game as they had started.
"One thing is to have international experience, and quite another to play against the best players in the world. In the second half we came on well and could have drawn, but we didn't."
