Portugal won Euro 2016 and are spearheaded by 39-year-old superstar striker Cristiano Ronaldo, preparing to play at a record-extending sixth Euros.

Ronaldo, the record men's international goalscorer with 130 strikes for his country, is also the all-time top scorer at the tournament with 14, a distance ahead of former France great Michel Platini in second spot on nine goals.

"I would say he represents inspiration, he represents that anything is possible, he represents all that you can dream, and achieve it," Manchester City centre-back Dias told a news conference Monday.

"Mainly I would like to say it's a pleasure to have him with us. More than all these little things or big things, him being with us in this moment of his career represents that he wants to win again.

"He's our captain and obviously we follow him to the end."

If Ronaldo scores at the Euros this summer he will become the competition's oldest goalscorer of all-time, breaking a record set by Austria's Ivica Vastic at 38 in Euro 2008.

Portugal coach Roberto Martinez said Ronaldo's experience could be vital at the tournament, along with veteran centre-back Pepe, 41.

"(Ronaldo) is very important... at tournaments, Euros and World Cups, the key is a mix of experience and new talent," said Martinez.

"Our team does it perfectly -- you mentioned Cristiano, and him and Pepe bring experience nobody else has, they are the two oldest players at the tournament.

"Then we have (the young players too)... we need all of this, they all need to be linked together, committed, that is crucial for us."

Czech Republic and West Ham United midfielder Tomas Soucek said his team could not afford to let their guard down against the Al Nassr striker.

"We all know Ronaldo's quality especially if you give him space," Soucek told a news conference.

"We can't give him an inch, especially in the area -- (there) we need to double our defence on him.

"Our goal is to stop him but obviously we need to stop the rest of the Portuguese team too."

If Ronaldo fires then Portugal may be able to live up to their billing as one of the favourites to win the tournament.

Martinez said he was aiming for that when asked if he had packed enough clothes in his suitcase to go the full distance.

"We must believe, we need to dream big -- if we don't dream big then it will be tough," he said.

"Tomorrow will be the right time to show we are ready, that we can meet all the expectations, but after the first three matches we can gauge whether or not we deserve to stay or not.

"I brought seven shirts, not three."