Defending champions Spain won 4-2 on penalties after both sides remained deadlock for 120 minutes. Ronaldo, however, missed a chance to take Portugal's fifth penalty as Joao Moutinho and Bruno Alves failed to convert from the spot.
"The penalties? I was going to take the next one," he said. "I was going to take the fifth penalty but we missed two," Ronaldo, who scored three goals in the tournament, said.
'The special one' Ronaldo, who failed to score against Denmark and Germany in Portugal's Group matches, scored two goals against the Dutch while his solitary header against the Czech Republic in the last eight, sealed a place in the semi-finals against their Iberian rivals Spain.
Despite having a better record against their neighbors, the reigning World and defending European champions were made to work harder than they would've expected. It was a 50-50 match which could also be described as a 'mini Clasico' given the stars from two La Liga giants Barcelona and Real Madrid.
Ronaldo had several chances to test his club team mate and goal keeper Iker Casillas but failed to hit the target with three free-kick opportunities, several shots off target and he also got the better of defender Alvaro Arbeloa, who in fact, gifted the ball to him on several occasions.
But when it mattered the most, during the penalty shoot-out, the Portuguese star only got to watch his side fail to convert from the spot.
Ronaldo revealed the penalty plan after the loss and said he was ready to step forward had Cesc Fabregas not scored Spain's winning penalty.
"It was just a question of me speaking with the coach. He said to me, 'Do you want to take the fifth one?' and I said 'yes'. Sometimes I take the first, the second or the third. I agreed to take the fifth," Ronaldo said.
Bruno Alves, who missed the fourth penalty, had come forward to take the third spot-kick but Nani intervened and slotted it home comfortably.
Meanwhile, Ronaldo hoped his Real Madrid friends can win the tournament. "I hope Spain win the tournament now because I have a lot friends there and I play there and it will be a tough final for them. It felt very normal playing against Real Madrid players. On the pitch we are not friends, but outside we are," he said.