Luis Enrique refused to speculate about how long Sergio Busquets may be out for after suffering a nasty leg injury in Barcelona's 3-1 Copa del Rey win over Villarreal on Wednesday.

Barca ran out comfortable winners to secure a 6-2 aggregate win and book their place in the final, though the match ultimately left a sour taste due to the injury to Busquets.

The Spain international was on the receiving end of crunching tackle from Tomas Pina, who later produced another wild challenge on Neymar and earned himself a red card.

Busquets was forced off on a stretcher with his ankle appearing to be crushed in the collision, but Luis Enrique was coy when discussing a potential injury lay-off.

"That [the injury to Busquets] was an unpleasant note,” the coach is quoted as saying by AS.

"In the absence of a diagnosis, he will be out for a few days. We must wait to see how many."

Despite ultimately claiming a comfortable win, Neymar felt it necessary to apologise to team-mate Luis Suarez after failing to set him up for a first-half goal, with the Uruguayan appearing somewhat frustrated.

"I knew we were two against one, but the space opened up so I went for goal," he added.

"These things happen sometimes, but we know and understand well what is best for the team and must always pass if it is possible.

"I apologise to Luis [Suarez] and I'll pass to him next time if I can."