Rayo Vallecano's Oscar Trejo celebrates scoring a penalty against Mallorca on Wednesday

Rayo Vallecano reached the semi-finals of the Copa del Rey for the first time in 40 years on Wednesday after they beat Mallorca 1-0 at a jubilant Vallecas.

Oscar Trejo's penalty just before half-time was enough to seal victory for Rayo, who will now attempt to make their first ever final in the competition.

The winner came in the 44th minute after Alvaro Garcia fooled Franco Russo with a sharp turn in the box and toppled over the sliding Mallorca defender. Trejo guided the penalty confidently into the corner.

Rayo returned to La Liga this season and have enjoyed a superb campaign so far. They beat Barcelona in October and now sit eighth in the table, with survival all but already secured.

They are only the fifth newly-promoted team in the top flight to make the Copa del Rey semi-finals this century.

Joining them in the semis will be either Valencia or Cadiz, who play later on Wednesday. On Thursday, Real Sociedad host Real Betis before Athletic Bilbao play at home to Real Madrid in the other two quarter-finals.