Watford head coach Quique Sanchez Flores does not know the extent of Etienne Capoue's knee injury but fears it could be serious.

The French midfielder suffered the injury during the first half of yesterday's FA Cup semi-final defeat to Crystal Palace after a collision with Yannick Bolasie. 

Capoue tried to carry on but he could not continue and was stretchered off after 31 minutes at Wembley. 

Flores said: “We don’t know exactly but it’s serious. It was impossible for us to keep Capoue on the pitch for us.

"It’s a pity because he is a good player for us and important. He’s one of the main players. It’s a knee injury but we don’t know exactly how bad it is."