Donetsk, Jun 28 (IANS/RIA Novosti): Spain reached their third-successive Euro final on Thursday, beating a defiant Portugal 4-2 on penalties after their Euro 2012 semifinal ended goalless after extra time.

Cesc Fabregas scored the winning penalty off the post to send Spain through, after Portugal's Bruno Alves hit the crossbar and Iker Casillas saved Joao Moutinho's spot kick.

Sunday's final in Kiev will be against Germany or Italy, who play in Warsaw Thursday.

Portugal shot out of the blocks as early pressure led to a Miguel Veloso corner that Iker Casillas had to pad over, such was the swerve.

But Spain pushed back immediately. A one-two between Andres Iniesta and Xavi was intercepted but defender Bruno Alves could only gift the ball to Alvaro Arbeloa, who side-footed over in the first clear-cut chance of the game.

Spain found out Cristiano Ronaldo was in the mood inside 10 minutes when the Real Madrid winger burst down the left to fire across a quick ball that Casillas just beat the onrushing Nani.

Ronaldo had an audacious attempt on the turn that sailed high, but showed his intent nonetheless.

Vicente Del Bosque's side went about trying to establish a passing rhythm with Portugal going all out to break it up, and to some extent succeeding.

Iniesta sidestepped a defender to fire just over half way through the first half.

But Portugal were not about to be dominated and forced a chance through Ronaldo, who turned Real Madrid teammate Sergio Ramos but could only drag left-footed wide from the edge of the box.

The physicality of the Portuguese approach had the Spaniards visibly rattled as they just couldn't settle on the ball, their movement impeded and passes over or under-hit.

The pattern continued into the second half as Portugal's Hugo Almeida, replacing the injured Helder Postiga, opted to shoot from range with Ronaldo free on the left.

The Besiktas forward, slipped through by Ronaldo, then stormed down the left but fired wide.

Del Bosque had seen enough, and reverted to the formation that brought more success in the quarterfinal against France, replacing anonymous forward Alvaro Negredo with Cesc Fabregas.

There was an immediate impact, with Barcelona teammates Xavi and Fabregas combining for the latter to win a dangerous free kick that the former nearly curled in.

Paulo Bento's side continued to frustrate their more illustrious Iberian neighbours and earned a free kick that Ronaldo blazed just over with a dipping effort from 30 yards.

The 27-year-old had another effort from the identical spot handled by Arveloa in the wall, but advancing 10 yards did him no favours as he failed to keep the follow-up down.

If Spain didn't look themselves it was at least partly down to an unusually quiet game from Xavi, and despite the prospect of half an hour of extra time looming, Del Bosque took the bold move of replacing him with Barcelona winger Pedro Rodriguez.

But it was the Portuguese who should have stolen it at the death, breaking five-on-three.

The final pass to Ronaldo was slightly behind him, however, and by the time he had worked it into a position to shoot, he blazed over under pressure from defenders.

Extra time was a predictably cagey affair with neither team willing to commit numbers forward to leave holes at the back.

But suddenly, the chance of the match fell to Iniesta toward the end of the first half as Pedro's tricks released Jordi Alba down the left, the Valencia wingback pulling across to the onrushing Barcelona midfielder who angled a tame effort that Rui Patricio palmed away with ease.

Sergio Ramos' Ronaldo-style free kick kissed the top of the crossbar to end the half.

The Spaniards marginally had the better of the second half too, as substitute Jesus Navas darted down the right, expertly held up his cross to watch defenders dive across his path before firing toward the corner. Rui Patricio padded it away and grabbed it at the second attempt.

Pedro then latched onto a Jesus Navas through ball to dash free, but the winger veered inside, too close to defender Pepe, who smashed the ball into the stands to clear.

When it came to penalties, both team had their first efforts save as Xabi Alonso went right and Moutinhno left.

Iniesta was the first to score, calmly sending Rui Patricio the wrong way. Pepe levelled it in the same fashion, before Pique squeezed it past Rui Patricio's outstretched arm and into the corner.

Nani lashed home confidently before Sergio Ramos was even cooler, chipping bravely down the center. Zenit St. Petersburg defender Bruno Alves opted for power only to see his effort crash down off the crossbar and out, setting the stage for Fabregas to put the Spaniards on the brink of history.

Spain began their title defence with a cagey 1-1 draw against Italy before crushing Ireland 4-0 and surviving a couple of scares to overcome a spirited Croatia 1-0.

Two goals from Xabi Alonso brought a 2-0 victory over France in the quarterfinal.

Portugal started their campaign with a narrow 1-0 defeat to Germany in Group B, but scraped through as runners up thanks to equally closely fought victories over Denmark, 3-2, and the Netherlands 2-1.

Ronaldo's 79th-minute header gave the 2004 finalists a 1-0 win over the Czech Republic in the quarterfinal.

Portugal: Rui Patricio, Bruno Alves, Pepe, Fabio Coentrao, Joao Pereira, Miguel Veloso (Custodio, 106), Joao Moutinho, Raul Meireles (Silvestre Varela, 112), Nani, Cristiano Ronaldo, Hugo Almeida (Nelson Oliveira, 80).

Spain: Iker Casillas, Gerard Pique, Sergio Ramos, Alvaro Arbeloa, Jordi Alba, Andres Iniesta, Xavi (Pedro Rodriguez, 87), Xabi Alonso, Sergio Busquets, David Silva (Jesus Navas, 60), Alvaro Negredo (Cesc Fabregas, 53).