Former Real Madrid manager John Toshack has warned Gerardo Martino that Sunday's El Clasico result could decide his future.

Martino, who took over managerial duties at Barcelona in the summer, has faced pressure in recent weeks from the local press with his side slipping to third place in the La Liga table.

Ahead of this weekend's Bernabeu clash, Toshack, who spent over 10 years in Spain as a manager, says that off-field issues relating to star player Neymar have had a negative impact on the club.

"You cannot say that he was unfortunate to arrive at Barcelona, it is a privilege, but things have occurred out of his control and have influenced the general support," the 64-year-old told Cadena SER.

"Any manager feels uncomfortable if they do not win whether in Barca or Benidorm. We live by results and successes, I wish the best for [Martino] but the result could judge his future."

Toshack has been out of management since resigning from his role at Azerbaijani club Khazar Lankaran in November last year.