Sevilla president Jose Castro has paid tribute to Monchi over the signing of Samir Nasri.

The on-loan Manchester City midfielder has been in spectacular form this season.

"When Monchi (sporting director) told me that he was considering signing Nasri, I thought immediately that he was insane.

"We simply cannot afford him," Castro told Cadena Cope.

"Nasri had limited playing time at Manchester City but has come here and he has a key role - Monchi has played a central role, but it also has been the club. We must be doing something right because there are players who have not succeeded in other clubs but come to Sevilla and triumph."