Euro 2012: Portugal v Spain, the key battles

The individual battles that will help decide who prevails in Wednesday's Euro 2012 semi-final between Portugal and defending champions Spain at Donetsk's Donbass Arena:

Cristiano Ronaldo (POR) v Alvaro Arbeloa (ESP)

A key confrontation between two Real Madrid team-mates, and one that is likely to have a strong bearing on the game's outcome.

Having scored the goals that took Portugal past the Netherlands and the Czech Republic, Ronaldo is in sensational form and he will fancy his chances against Arbeloa, who is rather leaden-footed for a modern right-back.

Arbeloa cannot compete with his club-mate for speed, so he will seek to prevent him from building up a head of steam by intervening as soon as Ronaldo receives the ball -- if not before.

Ronaldo destroyed Gregory van der Wiel in the game against the Dutch and lost Theodor Gebre-Selassie to head home the winning goal against the Czechs, but if Arbeloa can frustrate him, Portugal's chances of succeess will decline sharply.

Nani (POR) v Jordi Alba (ESP)

Ronaldo's fellow winger Nani faces a very different evening on the opposite flank, as Spain's left-back Jordi Alba is renowned for his forward forays.

France coach Laurent Blanc was so nervous about facing Alba that he aligned two right-backs in Saturday's quarter-final, only for the Valencia man to motor past them both to set up Xabi Alonso's 19th-minute opener.

Alba has a good understanding with Andres Iniesta and Portugal risk becoming overloaded on their right side if Nani does not track back to help out his right-back, Joao Pereira.

"We knew Spain's left side was very strong," said Blanc. "In Alba and Iniesta, they have two players who overlap constantly."

However, Nani forms a potent counter-attacking partnership with Ronaldo and the former Manchester United team-mates picked off the Netherlands at their leisure in the second half of the Group B encounter between the teams.

Joao Moutinho (POR) v Xabi Alonso (ESP)

Xabi Alonso stole the headlines against France with a brace of goals on his 100th international appearance but it is his distribution, rather than his finishing, that is central to the way Spain play.

The Real Madrid midfielder received more passes from his team-mates against the French (101) than any other player, which demonstrates that he is the man who most often sets Spain's attacks in motion.

If Portugal are to upset Spain's rhythm, Moutinho will have an important role to play in making sure that Alonso, Xavi and Sergio Busquets are not allowed too much time on the ball.

Alonso will also have to keep an eye on Moutinho though, as it was from the Porto midfielder's enterprising run and cross that Ronaldo scored Portugal's only goal against the Czech Republic on Thursday.

Pepe (POR) v Cesc Fabregas (ESP)

Spain coach Vicente del Bosque must decide whether or not to persevere with Fabregas in the 'false nine' centre-forward role, but given the control Spain exerted against France, that seems likely.

Although a capable goalscorer, Fabregas' key function in the role is his ability to drag defenders out of position and create gaps for Iniesta and David Silva to exploit.

"He gives us lots of fluidity in our play," says Del Bosque. "He has great control of the ball and increases the amount of possession we have."

Pepe is having a fine tournament for Portugal, but he and centre-back partner Bruno Alves will need to remain attentive to the darting movement of the former Arsenal man.

Pepe is also a hot-head, as he has demonstrated in some of Real Madrid's recent clashes with Barcelona, and he could get rattled if he finds himself overwhelmed by runners from the Spanish midfield.