Sergi Darder fired the decisive spot-kick as Real Mallorca beat Real Sociedad 5-4 on penalties to book their place in the Copa del Rey final on Tuesday.

With the two sides deadlocked at 1-1 following extra-time in the return leg after a goalless first leg, it was Mallorca who will line-up in the final in Sevilla at La Cartuja stadium on April 6.

The Balearic islanders will face the winner of Thursday's second semi-final - Athletic Bilbao taking a 1-0 lead into their home tie against Atletico Madrid.

After a goalless 140 minutes of play over the two legs, Uruguayan defender Giovanni Gonzalez finally struck to put Mallorca in control in San Sebastian.

Gonzalez latched onto a good cross from Jaume Costa to bury a close-range header past Sociedad's keeper Alex Remiro.

But just as Mallorca's thoughts began to turn to a first appearance in the Cup final in two decades Sociedad were back level with skipper Mikel Oyarzabal blasting home a nifty assist from Brais Mendez inside the box with half an hour of normal time remaining.

That set up a frenetic finale, but neither side was able to break the deadlock, resulting in extra-time, and then spot-kicks.

Oyarzabal was first to go only for the player who had kept Sociedad in the semi-final to miss, his shot well anticipated by Mallorca goalkeeper Dominik Greif.

Mallorca kept their nerve and with the teams level on 4-4 penalties apiece Darder stroked the ball into the bottom right corner, out of reach of Remiro's arm, to send Mallorca to Sevilla.

Mallorca, only two spots clear of the relegation zone in La Liga, now have a shot at adding to their lone Cup success back in 2003.

Sociedad, seventh in La Liga, will have to pick themselves up for next week's Champions League last 16 return leg against Paris Saint-Germain, who are in pole after taking the first leg 2-0.

Spain's two biggest sides, Spanish champions Barcelona and cup holders Real Madrid, were both eliminated in the last round.