Cristiano Ronaldo insists Portugal's mental strength can give them the edge when they come up against reigning world and European champions Spain at the Donbass Arena in Donetsk tomorrow.

The Real Madrid star has proved pivotal in his nation's recovery from an opening defeat to Germany, with two goals against Holland and the winner against the Czech Republic taking them to the Euro 2012 semi-finals.

Ronaldo is convinced coach Paulo Bento's men now have the toughness to go one better than their 2004 final loss to Greece.

And he is unfazed by the prospect of such daunting opponents standing in their way.

Ronaldo told "We lost our first match and then won all the others. I think that shows the great mental capacity of this team, and it didn't surprise me because I knew the goals would come.

"[Paulo Bento] is doing a great job, not only now but also during qualification. I think he's done a phenomenal job. From the moment he took on the national team he has believed in the players and is getting results in the final stage."

The former Manchester United star added: "I am not feeling the pressure of playing Spain or any other team because it is part of my life. I will always have responsibility but pressure? Not much."

Bento will be forced to make changes to his team as they bid to upset the odds and avoid a third semi-final exit in a European Championship after last-four heartbreak in 1984 and 2000.

The Portugal coach must decide which striker will replace the injured Helder Postiga, with Hugo Almeida favoured to get the nod to try to crack a Spanish defence unbreached in their last eight major tournament knockout games.

Almeida said: "I've worked hard to be called into the starting line-up and I'll take this opportunity. I was a little sad not to be included in the starting line-up but when the opportunity comes you have to be at your very best."