In the summertime, Welsh head coach John Benjamin Toshack asked for several changes, including the transfers of Bernd Schuster to local rivals Atlético Madrid and defender Oscar Ruggeri, together with midfielder Martín Vázquez, to Torino FC.

Following a losing streak sinking the team down to the 6th place in the league, Mendoza fired Toshack on 25 November 1990 and appointed club legend Alfredo Di Stéfano as a new head coach.

During February, forward Hugo Sánchez suffered his first injury,[7] and the squad was eliminated in the Copa del Rey round of 16 by Atlético Madrid.

After one game with Ramón Grosso as an interim manager, the club appointed Radomir Antić as a new permanent head coach.

Surprisingly, despite the chaotic situation and Hugo Sánchez out for the rest of season since 25 April,[8] Antic managed the squad to reach the third spot in the league standings and the right to play in the 1991–92 UEFA Cup.