Pep Guardiola’s side have enjoyed a record-breaking opening to the 2017-18 campaign to sit 14 points clear in the Premier League title race at Christmas.
Returning the crown to the Etihad Stadium now appears to be a formality, with unbeaten City having swept aside all before them in a run of 17 successive top-flight victories.
Neville, though, believes that success must be achieved over a prolonged period of time in order to be considered “great”, with Guardiola yet to join some iconic figures among English football’s elite.
The former United defender said in a podcast for Sky Sports: "I can't put City anywhere in terms of great teams as they haven't won a league yet.
"When they win a league, you'll say it's a great achievement. But to be one of the great teams in English football history, you have to win multiple leagues - you have to win two or three.
"The Chelsea team under Jose Mourinho, the United team under Sir Alex and the Liverpool teams over the years - they are all great sides. I can't say a team that wins the league once is truly great side - however, they are achieving great things.
"We've never seen anything like it. But, let's just calm ourselves, and respect the bigger picture. I think they have to win more than one league championship and a European cup before they become a great side."
City hold such a commanding advantage as the chasing pack has been unable to keep pace.
Closest challengers United dropped another two points in their latest outing, with Mourinho’s side allowing Leicester to snatch a last-gasp leveller in a 2-2 draw at the King Power Stadium.
Neville was less than impressed by the Red Devils’ inability to see that game out, with a communication breakdown leading to a clearly injured Chris Smalling being left exposed as Harry Maguire stole in to snatch a dramatic equaliser.
The ex-England international added: "Smalling has got to flag up as an experienced defender that he's struggling, get someone else into the centre.
"It didn't happen for two or three minutes.
"Then Phil Jones recognised it had happened and tried to reorganise - as I saw it, Ander Herrera refused to go to right-back and told Henrik Mkhitaryan to go back there. All over a sudden Smalling sits down on the floor and then goes off the pitch and then comes back on at centre-back. He ends up picking up Harry Maguire.
"You can't believe the disorganisation and lack of leadership shown by Manchester United at the end of that game in a game they should have won. Jose will be furious when he watches that back."