At 19, it was his first major tournament
Euro 2004 was supposed to be the moment an avid football nation like Portugal finally won a major tournament.
But like every other nation that faced an unshakeable Greece side, the Portuguese could not find a way through.
Indeed, Portugal lost twice to the Greeks - first in the tournament's opening game and then in the final.
Even more painful was the fact that Portugal were hosting the tournament at a time when the golden generation of Luis Figo, Rui Costa et al were at their peaks.
It was supposed to be the moment but unfortunately, Portuguese tears were the image that was left for the world to see.
Cristiano Ronaldo had had one season of Premier League football for Manchester United when he got called up for Euro 2004 and had an immediate impact.
Even though Portugal did lose to the Greeks in the opening game, Ronaldo had an immediate impact, with a stoppage time consolation goal in the 2-1 defeat. As Wales found out at Euro 2016, that type of header from a set-piece has been an important part of his attacking Arsenal.
The future Ballon D'Or winner had yet to exit his teens at that point and for many, would still have been regarded as the slightly frustrating but exciting winger of that time.
Portugal's Luis Figo (r) goes to shake hands with teammate Cristiano Ronaldo (l) as he comes off the field against Russia. Picture by: Mike Egerton / EMPICS Sport
But his potential was as clear as daylight and as then-Portugal boss Luiz Felipe Scolari later told Omnisport, Figo took Ronaldo under his wing in training as one legendary winger imparted knowledge to his successor as both star and captain.
Scolarli recalls: "When Ronaldo started with the national team, the first one to help him was Figo. He was the first player to challenge Ronaldo to dribble and shoot, to score goals, to play his own game, to keep working all the time and become a better footballer.
"Figo took a position, saying 'My son, try again, keep trying. If you see the situation is difficult, I will give you a hand, and if you make a mistake I have everything ready, so calm down, but you have to try.'"
For the first Greece game and the 2-0 group win over Russia, Ronaldo remained an impact sub. But for the final group game against Spain and the remainder of the knockout stage at Euro 2004, the then-Man United starlet had earned his place in the starting line-up.
Portugal's Cristiano Ronaldo (c) cries at the final whistle. Picture by: Mike Egerton / EMPICS Sport
And by semi-final time, he would score his second goal of the tournament in the 2-1 victory over the Netherlands that would book Portugal's place in the Lisbon final against Greece.
We know how that ended, with Ronaldo in tears as the Greek's spoilt the home nation's party.
But 12 years on and Ronaldo has a second chance to lead Portugal to European glory and this time as the underdog who could spoil a home nation's best-laid plans.
France will be wary in Paris but Ronaldo will be driven by the pain of 2004.