The former Red has backed Liverpool to make a serious tilt at the Premiership title after seeing them close up as he played against them for Preston on Saturday.
"Liverpool have advanced massively since I left. We watched videos of them before the game and they really do look an organised side," said Mellor.
"They pass it all over the pitch and from that performance it's clear they are going to get close to the league title which is what the fans have wanted for 19 years.
"They are top of the table now and I'm sure Rafa will want to win every game they go into, but the league title will probably be the most important thing for them this season.
"If he keeps his players fit, they'll have a great chance. You just watch their passing and it's incredible."
