Ricardo Quaresma says Portugal must earn the right to be considered a challenger for Euro 2016 with strong performances in their warm-up games, beginning with Norway on Sunday.
Fernando Santos' side - in eighth place - are the fourth-highest European nation in the current FIFA rankings and have been tipped as one of the favourites to win the finals in France.
Inspired by captain Cristiano Ronaldo, who scored five goals in qualifying to guide his side to top spot in Group I, Portugal are hoping to go one better than in Euro 2012, when they lost to eventual winners Spain on penalties in the semi-finals.
Quaresma, however, has denied that they should be considered clear candidates to end their long wait for a first ever major title - but is determined for them to prove their quality when they face Norway, England and Estonia in friendly matches over the next 10 days.
"Favourites? No, we're a team that's very ambitious to win and that's what we're working towards, but we're not favourites," he said this week.
"We lack titles. Germany, France, Spain have won titles, so we can't compare ourselves with those teams. We have to keep working and show where we want to get.
"We're confident and we have a clear head. The group is fantastic. We have a great motivation and a great team spirit. We have to get to the Euros in the best condition."
Norway narrowly missed out on a place at Euro 2016, finishing a point behind Croatia in qualifying Group H after their 2-1 final-day defeat to winners Italy before losing in the play-offs to Hungary.
Head coach Per-Mathias Hogmo is now looking forward to facing Portugal in Braga before matches against Iceland and Belgium at the start of next month.
"It's a useful experience to face these teams before qualifying starts," said Hogmo, whose side beat Finland 2-0 in March. "It was a nice experience last time.
"We know that all three of these will be tough games, but it gives us some useful reference points."
Portugal will be without Ronaldo and centre-back Pepe as a result of Real Madrid's Champions League final commitments, giving a number of players the chance to impress Santos in the absence of the talisman.
Norway are expected to rest Havard Nordtveit due to illness, while Omar Elabdellaoui (knock), Alexander Tettey (ankle) and Alexander Soderlund (tendon damage) have not recovered from injury concerns. Youngsters Iver Fossum, Ulrik Yttergard Jenssen and Alexander Sorloth could all be involved.