The Sky Sports pundit said:
"Ajax, Manchester United and Barcelona are the three bastions of European football in terms of style of play. United have always played 4-4-1-1, 4-4-2, with two wide players. It's ingrained in the club. Don't change, don't make short-term decisions.
The fans weren't happy, the stadium was starting to have empty seats and then they think, 'right, we need to win' and they bring in Jose Mourinho, who likes powerful, robust, strong players."
Mourinho's team have failed to set the Premier League alight, finishing 19 points behind champions Manchester City last season as runners-up.
The Special One has installed the stylistic qualities of his former Chelsea and Inter Milan sides, with Red Devils supporters left wanting more entertainment.
"Out went nearly all those 11 and Mourinho brings in [Romelu] Lukaku, [Nemanja] Matic, Fred, [Eric] Bailly, a wave of players who suit his style. Let's say Mauricio Pochettino comes in next - he likes hungry 23, 24-year-olds, he likes pushing up the pitch and playing high, he likes players who can press from the front.
How many Manchester United forwards do you see that run about like the Tottenham [Hotspur] ones? Mourinho is happy to sit back a bit deeper and have a more robust, physical player.
As a Manchester United fan it's painful to watch."
Neville's assessment will be a stinging blow to Mourinho and the team, with the former skipper still hugely popular at the Theatre of Dreams.
The former Real Madrid manager has steadied the ship after the tenures of David Moyes and Louis van Gaal, finding immediate success with victories in the UEFA Europa League and the EFL Cup in his first season.
However, Mourinho has now entered his third term, and United fail to resemble the attacking force of old that garnered much success under former manager Sir Alex Ferguson.
United fans will demand a stylistic change if the team fail to win silverware this season, with City playing a brand of football that is the envy of Europe.
Mourinho must find a way of bringing the best out of Paul Pogba at the heart of his midfield, as United struggle to produce the flair that's expected at Old Trafford.