The Real superstar thanked his supporters for the reception they gave him following his Ballon d’Or win earlier this week.
But he could not deliver a win as Atletico held them to a 2-2 draw – courtesy of a double from Fernando Torres – to advance 4-2 on aggregate.
And Ronaldo spoke post-match on his lack of fitness at the moment and slammed the approach of Diego Simeone’s men.
In the name of the team, I can only apologise to the fans, because we could have done better in the second half.
I appreciate the support we received on the bus, and the reception they gave me before the game.
Ronaldo then turned on Atletico – who have set up a Copa quarter-final clash with Barcelona after last night’s winner.
Atletico do not play attractive football. They are very defensive.
They are always waiting for set-pieces, but it works well for them. You must respect their players and their coach.
The defeat added to a horror start to 2015 from the Champions League winners.
Real won 22 games on the bounce at the end of 2014 but have won just one in four at the start of this year.
As for Ronaldo’s performances, the Ballon d’Or winner believes he’s not at his peak fitness, saying:
You cannot score in every game, or be at your best.
Tell me a player who always plays well. I am not from another planet. Maybe I am not perfectly fit, but I will be there.
The knee issue is over, I have got used to playing with pain. In two or three weeks I will be fine, and the team too.
Ronaldo’s comments are sure to anger Atletico fans who may feel their side is only playing to Madrid’s weaknesses.