Portugal midfielder Vitinha said on Friday his country's star-studded squad must prove they are a "great" team at Euro 2024.
The 2016 champions face the Czech Republic on Tuesday in their opening fixture, having qualified for the tournament with a 100 per cent record.
However Portugal fell to a friendly defeat by Croatia last week and question marks remain over whether they can cope in the biggest games.
Led by superstar Cristiano Ronaldo, Manchester United playmaker Bruno Fernandes and other leading stars including Joao Felix and Bernardo Silva, expectations are high.
"We have a great team, with great players playing for great clubs... but great teams prove themselves on the pitch, not in theory," Vitinha, who plays for French champions Paris Saint-Germain, told a news conference.
"That's what we have to do at this European Championship, to reinforce the idea that we're a great team.
"We have great players and it's important that we show that on the pitch. That's the only way we'll become what everyone says we are."
Portugal were received by thousands of fans upon their arrival in Germany, keen for a glimpse of Ronaldo and his teammates.
"It was an unbelievable reception, both at the airport and at the hotel," continued Vitinha.
"People were recording inside the bus, we were recording (the fans) outside, because it was crazy."
Vitinha enjoyed a strong season with PSG, scoring nine goals from central midfield.
"It's been an incredible season for me, personally and on a collective level, there was no better way to be ready for the Euros," the 24-year-old added.
"I feel motivated, I feel prepared and I'm looking forward to kick-off, and being able to help the national team at this European Championship, my first.
"I'm here at the best moment of my career, playing important games in the biggest club competition, the Champions League, winning the French league, being important at club level... I guess you could say I'm at the top of my game."