Cristiano Ronaldo insists he is not concerned by the pressure to perform for Portugal ahead of their Euro 2012 semi-final with Spain.The Real Madrid man has acknowledged that criticism is part and parcel of being a successful footballer, but he simply acts the 'bigger man' and ignores any negative press.After coming under sustained pressure from the media in his homeland following two below-par performances his output improved, but he says it is his own standards, and not those of others, that drive him to success."The bigger star you become, the greater pressure there is on you to perform at a level acceptable to other people let alone yourself," he said."Even Messi has his critics. You can't please everyone. But I don't get angry or frustrated by it."I accept its part of being a professional footballer, it comes with the territory. It takes a bigger man to ignore it and just get on with playing."I don't have an agenda where I set out to appease critics. I just go out and play to the best of my ability."After a slow start to the tournament, Ronaldo has found some blistering form and now believes that Portugal can go on and reach the final.He praised the unity within Paulo Bento's squad, and said that their spirit has helped them to get through a tough group and on to the semi-finals."We're improving and that's important," he said."There is great unity in our squad, we've a good team spirit and that helps."It's been difficult to get this far, but we reach this stage with a great deal of optimism no matter who we face in the semi-final."Our objective now is to reach the final. Why not? There's greater pressure on other sides in this tournament and we've been able to progress without excessive expectations."No matter what happens now we should all be congratulated."