Chelsea brought in the World Cup winner on deadline day after a drawn-out saga where it was not clear the Blues would get their man even after their efforts.
The fee for the midfielder is a staggering £106.8m and fans will hope that Fernandez will recoup the money spent with his performances, especially with Jorginho having left them for Arsenal.
For Murphy, Fernandez is a good footballer but not up to the standards of Manchester City star Rodri or Manchester United man Casemiro.
The Liverpool legend also went on to criticise Chelsea’s transfer business, insisting the Blues are being taken advantage of by other clubs.
Speaking on talkSPORT, Murphy said: “He is a good midfielder, he’s tenacious, he’s young, he gets on the ball, he’s brave.
“But he’s not Rodri, not Casemiro.
“They’re overspending on players, people are seeing them come and they’re just taking their pants down basically.”
Rodri and Casemiro are both older than Fernandez, who played 29 times for Benfica prior to coming to Chelsea and scored four goals along with providing seven assists.
