Spain defender Alvaro Arbeloa says he is psyching himself up "mentally and physically" to face Real Madridteam-mate Cristiano Ronaldo in the Euro 2012 semi-final against Portugal on Wednesday.

With three goals in his last two matches, Ronaldo has emerged as one of the stand-out players at the tournament and Arbeloa will enter directly into his line of fire when the teams face off in Donetsk.

The 29-year-old right-back will be chiefly responsible for keeping Ronaldo in check at Donbass Arena, and he admitted he was not expecting an enjoyable evening.

"You have to be prepared mentally and physically, especially against someone like this," Arbeloa said on Tuesday.

"He's one of the best players in the world. It's very demanding, physically and mentally. You have to be on top of your game.

"You can't stop him for the whole 90 minutes, but it's a great challenge for me. I like to measure myself against the best in the world.

"I haven't spoken to him. I will probably speak to him tomorrow, when I see him, but we don't know the starting line-ups yet.

"If I'm lucky, the coach (Vicente del Bosque) will put me there and I'll play against him. We all know his level's been very high at this Euro.

"He's very difficult to play against and very confident, but we will try to stop him."

Arbeloa added: "It's not easy to stop Ronaldo. He has scored three goals and has played some really good games.

"But we know Portugal are not just about Cristiano Ronaldo. They have lots of good players, like Nani, who are having a good tournament. They have players with lots of quality and we have to stop all of them."

Aside from Ronaldo, Arbeloa can also expect to come up against his other Madrid team-mates Pepe and Fabio Coentrao.

Asked whether it will feel strange to find himself on the opposite side of the halfway line to his club-mates at kick-off, he said he would be too focused on helping Portugal reach the final to notice.

"It's the same as when you play for your club and you play against your mates from the national team," he said.

"Tomorrow I play for the national team, and I won't be mates with my club-mates. It's important to know who you play with and who you play against.

"I might talk to them during the game, but I'll be fighting for us to get through to the final."

Portugal are bidding to reach their first major final since they lost 1-0 to Greece as hosts at Euro 2004.