Barcelona and Real Madrid are well placed to reach the final of the Spanish cup after emphatic semi-final first leg home wins on Wednesday.
Barca beat Real Sociedad 2-0, and Real Madrid thrashed holders Atletico Madrid 3-0. The second legs will be February 11 and 12.
Only 39,000 fans turned out for the Barca-Sociedad clash in the massive Camp Nou.
Sergio Busquets gave Barca the lead just before half-time after the Sociedad defence failed to clear a corner. Sociedad then had defender Inigo Martinez sent off for protesting about a penalty not awarded for the visitors.
Sociedad suffered a further setback on the hour when a clearance from Gorka Elustondo toward his own goalkeeper Enaut Zubikarai went in for a bizarre own goal.
Barca squandered excellent chances to settle the tie with more goals towards the end.
Earlier Wednesday, a 3-0 home defeat of neighbours Atletico Madrid left Real Madrid well placed to reach the final.
Atletico had none of the good luck they enjoyed when they beat Real 2-1 in last season’s final, their first derby win since 1999.
Defenders Emiliano Insua and Joao Miranda scored unfortunate own goals for the visitors.
Insua’s own goal came in the 18th minute when he deflected in a shot from Real defender Pepe that was going wide.
In the 58th minute Angel di Maria set up youngster Jese to make it 2-0 with a clever low toe poke. A long drive 16 minutes later from man-of-the-match Di Maria took a wicked deflection off Miranda and went in to make it 3-0.
“It was our best game of the season so far. Even so, the tie is not settled yet,” Real coach Carlo Ancelotti said.
“My players worked very hard tonight, and we were a very compact team.” Meanwhile, Atletico boss Diego Simeone said, “Their first goal was a bit freakish, it has to be said. But from then on they were the better team - I have to admit that.”