Ronaldo, 39, watched that match from the bench but started against Ireland in Aveiro and came close in the first half before dismantling the visitors in the second.
Veteran defender Pepe, 41, set to become the oldest player ever to play at the Euros, also started.
Euro 2016 winners Portugal qualified with a 100 percent record but recent performances had allowed some doubts to creep in.
“The Portuguese expect a lot from Portugal, there’s no margin for error, none, they always want Portugal to win because of the generation, the talent there is,” said Ronaldo.
“We have to have our feet on the ground and our thoughts in the sky, dreaming of the Euros.”
Ronaldo will appear at a record sixth edition of the tournament, having played in his first back in 2004.
“Going back to 2004… my thoughts and my pride remain the same,” said Ronaldo.
“Playing for the Portuguese national team, it doesn’t get better than this.
“For the Euros we have to think positively, this team has to dream and has been working hard, because just having talent is no use if there’s no hard work.”
Felix broke the deadlock with a smart finish after a short corner routine in the 18th minute.
Ronaldo almost made it two but his deflected free-kick struck the post.
The Al-Nassr striker appealed for a penalty after falling under pressure and then fired a decent opening straight at Caoimhin Kelleher towards the end of the first half.
Ronaldo did not have to wait much longer to score, pouncing soon after the break with a sublime effort curled into the top corner.
The former Real Madrid marksman soon grabbed another after Diogo Jota found him well placed in the area.
Ronaldo netted a record-extending 130th international goal with another confident finish.
The striker fired inches wide when he might have completed his hat-trick as Ireland, under interim coach John O’Shea, began to tire, although Portugal could not add to their lead.
“The game against Croatia served to bring us down a peg and today we did a great job, it’s about following this line,” said Felix.
“We have 100 percent confidence on the way to Germany.”
Euro 2024 begins on Friday and Portugal’s first match is against the Czech Republic on June 18, before facing Turkey and Georgia in Group F.
© Agence France-Presse
Photo: Twitter @selecaoportugal