Fast forward to the beginning of the 2017/18 season and the club are already on their third permanent manager since Ferguson's departure following the dismissals of both David Moyes and Louis Van Gaal in 2014 and 2016 respectively.
Despite the Citizens looking a force this season, Guardiola has admitted that United now look like a team managed by his rival.
Anthony Martial is playing some of his best football at the moment.
"We have to wait for them", Mourinho concluded.
"They've got (Nemanja) Matic in there (now), they've got a more dynamic striker in (Romelu) Lukaku, who obviously hasn't got the quality of (Zlatan) Ibrahimovic".
Manchester City secured a statement victory at Stamford Bridge against champions Chelsea, Tottenham maintained their ideal away record, and Watford continued to entertain neutrals with another attacking display. By the looks of how the season is going, he has done just that.
De Bruyne left Chelsea for Wolfsburg in January 2014 and the Belgian moved to Man City for £58m 18 months later.
City have scored 17 goals and kept four clean sheets in their past four Premier League matches. Only two of their opponents so far finished in the top 10 last season.
In fact, before their thumping 5-0 win over Klopp's side in September, Man City had failed to beat Liverpool in the league in their last five meetings, with Liverpool winning four of those.
Liverpool knows a win on home ground will send a message to the rest of the top flight.
Mourinho and United will finally get their chance to send out a similar message after the worldwide break.
Liverpool have struggled slightly of late.
Harry Kane is now scoring goals for fun and he will most certainly test Phil Jones, Eric Bailly and maybe even Victor Lindelof. The Welshman was always renowned for his defensive solidity, but has added attacking verve to his repertoire his term.
"In another league it could be said that a team that starts with seven wins and a draw would nearly mean the title, but in England it doesn't mean anything, not even that we will finish in the first four places".
But they haven't played anyone!
If United can go to Liverpool and win, managing also to keep a clean sheet, it will be more than enough to prove that this team have what it takes to push City right to the end.
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