The first Euro 2012 semi-final tonight will see Spain look to book their place in the final as they bid to retain their European crown and reassert their authority as the world's best team.
Neighbours Portugal will be aiming to cause an upset by knocking the holders out.
Here we look at the key battles on the pitch which could decide the game.
FERNANDO TORRES V PEPE
Torres' season ended with a flicker of hope of recapturing his former glory, and despite a shaky start to the tournament as a substitute against Italy he proved his worth scoring twice against Ireland.
He will need to produce this kind of performance and more if he is deployed as the centre forward by Vicente Del Bosque as he will be facing Portugal's defensive commander Pepe whose strength and awareness will make his side difficult to break down.
Supremely confident, with a goal to his name in the competition and coming off the back of a title-winning season at Real Madrid, Pepe has shown he can handle any of the top strikers around. Torres cannot allow his form to let him down if he wants to unlock the Portuguese defence and send Spain through.
CRISTIANO RONALDO V ALVARO ARBELOA
The two Real Madrid team-mates line up opposite each other. Ronaldo will be terrorising the left wing, as well as dropping into a more central position to help create moves when required, whilst Arbeloa is operating in the right-back position for his national team.
Ronaldo is not only instrumental in constructing many of Portugal's moves, he is often there to finish them off too, as he has shown with three goals in the final two group games.
Arbeloa will have to track him well and communicate with his team-mates in order to deal with the the threat. If Spain fail to keep Ronaldo in check, Arbeloa knows better than most what he is capable of.
XABI ALONSO V JOAO MOUTINHO
Madrid's Alonso, known as a solid and reliable holding midfielder, came to the fore in Spain's quarter-final against France as he scored twice.
Moutinho can operate in a similar holding role, but has looked threatening in a more advanced position so far in the competition, supplying two assists and providing dangerous balls to the forwards and out to Ronaldo and Nani on the wings.
Both will look to stifle their opponents, although with Spain's possession-dominated play, Porto man Moutinho could be set to do the most running. Both will also look to get forward in support of attacking moves.