The Real Madrid star hit the bar with a 79th-minute penalty on Saturday, missing the chance to become the first player to score at four Euro Championships.
The result means CR7 and his misfiring teammates need to beat Hungary in their final Group F this Wednesday (kickoff 9pm) to make knockout phase.
Ronaldo says: “We need to think that it’s still possible; if we win, we qualify.
“And also the Portuguese people, the fans who love Portugal, they also have to believe in it.
“I missed some chances - a penalty and some other chances, but that’s part of football. We need to continue to believe.”
“The bad won’t last forever, so we need to believe that things will go better.”
The Real Madrid ace also saw a late headed goal disallowed for offside after he missed a couple of simple chances.
Ronaldo was celebrating his 128th cap for his country, passing Luis Figo’s total of 127.
And he adds: “It’s a reason to be proud, reaching 128 international matches and beating the legendary Figo.
“I know deep down he is also proud of that. Obviously it was a goal to be the most capped international player, and also to be the national team’s top scorer.
“But obviously I’m a bit sad, because this wasn’t the way I wanted to break this record. The most beautiful way would have been… to win, and we couldn’t.”