Cristiano Ronaldo said Portugal must be realistic as they are not among the World Cup favourites, though the Real Madrid superstar insisted nothing is impossible.

Euro 2016 champions Portugal will face Spain (June 15), Morocco (June 19) and Iran (June 25) in Group B at the World Cup in Russia.

Portugal defied the odds to be crowned European champions two years ago and captain Ronaldo – who is set to return to the starting XI for Thursday's friendly against Algeria having enjoyed some rest following last month's Champions League triumph – said Fernando Santos' men will give their all at the showpiece tournament.

Led by Ronaldo as Portugal were sent off to the World Cup at a Lisbon reception held by president Marcelo Rebelo De Sousa Wednesday, the five-time Ballon d'Or winner said: "What I can guarantee is a great ambition of all of us players and technical team.

"We know we are not the favourites, we have to be realistic, but in football nothing is impossible.

"I think we must think match by match. The first match, the group stage will be extremely difficult but I think that with these players we need to think big and I am confident that we will give our best."

"What I can say is that we will do the same [of Euro 2016] fight to the end always keeping hope that in football everything is possible," Ronaldo – Portugal's most capped player and leading scorer – continued.

"Step by step see what will happen, what the competition will bring us and for us is a privilege to represent Portugal's colours [and] represent this nation.

"We will give our best and wait to see what we will get from it. Thank you very much to have us here for us is a privilege, thank you very much."