With his customary coolness, Ronaldo answered those doubts in spectacular fashion with two goals that guided Portugal into the last eight at Euro 2012.
Since that performance, praise has poured down upon Ronaldo for finally showing his best and on his team as having emerged as a potential threat to win the competition.
But there is a serious danger of over-hyping the display from both Ronaldo and Portugal.
On that day, Paulo Bento's side encountered from the Dutch one of the worst defensive performances seen in a major tournament in many a year. An already weak backline, featuring an 18-year-old left-back in Jetro Willems looking cruelly out of his depth, was further exposed by having just Nigel de Jong shielding it and five players with license to attack with little defensive responsibility.
Perhaps the question should be asked how did Portugal only score two goals against such an inviting defense. Certainly Ronaldo had opportunities to add to his tally, as did Helder Postiga who, despite his goal against Denmark, remains an unreliable finisher.
When Portugal takes on the Czech Republic in the first quarterfinal on Thursday, it is Ronaldo that will once again very much be to the fore. It is not just that he will be the outstading player on show, but the forward will also be involved in what is likely to prove the key duel in the match, up against one of Euro 2012's stand-out performers, Czech right-back Theodor Gebre Selassie.
With Tomas Rosicky still a doubt to return from an Achilles tendon problem, Gebre Selassie, as he was against Poland, will be crucial to providing much of the Czechs' attacking impetus. His bursts forward will also enable one of the side's other key contributors Petr Jiracek to have space to cut in from his wide-right role. It was no coincidence that Jiracek got the vital goal doing just that against the Poles.
It could very much be a game of dare between Ronaldo and Gebre Selassie in Warsaw. Ronaldo is unlikely to do much tracking back, allowing Gebre Selassie free-reign to charge up field and threaten another offensive-minded full-back, Fabio Coentrao. The conundrum for the young Czech is whether to take up the offer given that he would potentially leave his side open to the kind of quick breaks that Portugal and Ronaldo profited from against the Dutch.
It is far from a solitary counter-attacking threat that Portugal pose, however. It may be Ronaldo who has garnered all the headlines, but it is the man who has long lived in his shadow, both at Manchester United and for his country, Nani, who has been Portugal's outstanding player so far at Euro 2012.
If the Czechs are to make their third European Championship semi-final in just five appearances then both Nani and Ronaldo will have to be kept closely under wraps. Were that to be achieved then the Czech Republic would fancy their chances given that the rest of the Portugal side lacks the sparkling quality of their sprightly wingers.
The Czechs were crudely opened up time and again in their opening match of the tournament against Russia. Since then, though, coach Michal Bilek has learned his lesson with Tomas Hubschman coming in to endow the team with a vital shield in front of the back four.
But with Rosicky, even if he starts, unlikely to be at full fitness, the Czechs are sorely lacking in creativity. His replacement Daniel Kolar has shown very little in the game and a half in which he has deputized for the sides' talisman. Vaclav Pilar has shown potential, but, going forward, no-one adds the same invention on the ball as Rosicky. And, with Milan Baros looking a shadow of his former self it is very much a blunt Czech team, relying on industry rather than inspiration to prosper.
The Czechs have the ability to make it tough for the Portuguese but all the match-wining quality is on the side of the Seleccao das Quinas and that should eventually tell.
Portugal 2-1 Czech Republic