Porto announced on Saturday that Del Neri's contract had been terminated "for personal reasons", and the club wasted no time in appointing Fernández, reaching agreement on a two-year deal with the Spaniard after negotiations late on Sunday night.
Del Neri was hired by Porto in June to replace the Chelsea FC-bound José Mourinho, but departed the Estádio do Dragão without taking charge for a single competitive fixture. The 43-year-old Fernández was able to succeed him immediately as he was out of work having left Real Betis Balompié at the end of last season.
He said: "It is a great challenge. I am going to be in charge of one of the biggest teams in Europe, and the fact that they have won so many titles recently does not scare me. After what has been achieved here in the last two seasons, it would not be intelligent to cut ourselves off from the past."
'The right time'
Fernández added: "I accepted the invitation because this was the right time. There has been contact on previous occasions but we could not meet. Finally, both the club and myself could meet. So I am very honoured and proud."
Fernández is highly respected in Spain after winning the UEFA Cup Winners' Cup with Real Zaragoza in 1995 and a successful four-year spell at RC Celta de Vigo, in which the team reached the UEFA Cup quarter-finals for three consecutive seasons.
Summer of speculation
He left Celta for Betis in 2002 but parted company with the Seville club earlier this summer. He had been linked with the coaching vacancies at Real Madrid CF and the Spanish national side before securing his future with the Portuguese champions. Girona FC sports director Narcís Julià will be Fernández's assistant with José Luis Arjol as fitness coach.
Porto begin the defence of their SuperLiga title on 29 August, before starting their Champions League group stage campaign in mid-September.
©UEFA.com 1998-2014. All rights reserved.