Portugal vs. Spain Euro 2012: Keys to Portuguese Upset over Defending Champs

Portugal can spoil Spain's bid to defend the Euro 2008 title with an upset victory in Wednesday's semifinal at Euro 2012.

A Portuguese victory hinges on a handful of important factors and one iconic player. Cristiano Ronaldo must be in top form and his supporting cast must do their duty.

An upset bid is not out of the question. Portugal is gaining steam, but this is their biggest test yet. 

Let's take a look at what Portugal needs to do to advance to Sunday's Euro final.

Attack From Wings

Ronaldo and Nani are two outstanding offensive talents. Portugal must use their skills to exploit Spain's outside defenders.

Spain's right back Alvaro Arbeloa isn't a bad player, but Ronaldo is on a different playing field. CR7 can control the pace of an entire game by himself, and Arbeloa presents that opportunity.

Jordi Alba has done a fair job replacing Joan Capdevila at left back, but Nani has been a consistent offensive presence for the Portuguese side. His explosive quickness from the right wing gives his squad a dangerous No. 2 option.

Arbeloa and Alba will both face stiff challenges. Portugal has an advantage on the wings, and they must feed Ronaldo and Nani constantly.

Make Key Saves

Rui Patricio has had a fair but not overwhelming tournament. He's allowed four goals and come up with a number of timely saves.

In the quarterfinals, Patricio pitched a shutout against the Czech Republic. He must build on that momentum against Spain's ultra-talented attack.

Patricio is going to face shots from all angles. Spain is strong up the middle, and David Silva and Andres Iniesta are two of the world's best midfield players. Xabi Alonso and Xavi are two creative players in the midfield, and Cesc Fabregas is always an option as an attacking threat.

Spain can strike from anywhere.

Patricio must be ready to make a timely save for his squad. Making a few big saves early in the game would hand momentum to his side and possibly propel them to victory. On the other hand, an early deficit could take them out of this game quickly.

Play With Confidence

Portugal must play with a swagger against their Spanish counterparts. Spain is the defending Euro champion. They have everything to lose, but no one really expects Portugal to win.

The Portuguese squad must play loose, but focused. They must embrace the underdog role and allow perhaps the world's best attacker to play his game. Ronaldo's top form invigorates Portugal's overall energy.

Portugal's side doesn't quite measure up to Spain's on paper, but the cupboard isn't bare. I already mentioned their wing play, but Joao Moutinho is stable in the midfield as well.

Centre-backs Bruno Alves and Pepe provide above-average defense, while Joao Pereira and Fabio Coentrao are spotty outside backs at times. Having said that, both are capable of pushing the ball up the field.

Portugal must be confident in what they have. Spain has the pedigree, talent and recent success, but this game is still up for grabs.

This has nothing to do with the ball, but it may be the game's most important factor. Portugal must arrive with confidence, and they must play focused for 90-plus minutes of football.