Portugal will look to justify their tag as favourites in the Euro 2012 play-off second leg match with Bosnia-Herzegovina tonight and seal their place in a fifth successive European championships.

Focussed: Portugal skipper Cristiano Ronaldo. Pic/AFP

The Portuguese -- finalists when hosts in 2004 -- largely dominated the first leg which finished in a 0-0 draw in Zenica on Friday but will be counting on stars such as Cristiano Ronaldo to see them safely on the plane to Poland and Ukraine next year.

The two sides know each other well, having also faced each other in the play-off for a place at the 2010 World Cup which the Portuguese took only to disappoint at the finals themselves.

"It's pretty much equal," Ronaldo told uefa.com. "Of course we'll be playing in better conditions, with our fans behind us, at home, but it'll be just as difficult. We got a good result away from home and we have to finish things in our home game," the 26-year-old Real Madrid superstar added.

"We have to take on the mantle of favourites because we're a team that always has a chance of winning," he said. "So we have to prove why we're favourites on the pitch. There's no point in just talking about it and not proving it in matches."