And Dugarry, who won the World Cup with France in 1998, believes the Portuguese boss and new striker Zlatan Ibrahimovic are at the root of the problem.
Ibrahimovic has scored four goals in his first five for the Old Trafford club and arrived in England after a record breaking season for Paris Saint Germain .
But Dugarry, who played for AC Milan, Barcelona and Marsellie during his career, believes the 34-year-old is not mobile enough for the English game.
"Ibra is a cone. People talk about his stats… but he's a cone," Dugarry said on his RMC radio show.
"When you see Zlatan's matches, it's not possible to do that. It's English football, it goes at 2,000 kilometres an hour."
Dugarry was even more scathing of Mourinho, whose last tactical triumph he said was six years ago.
"I get the feeling Mourinho's last tactical success was that Champions League game between Inter Milan and Barcelona," Dugarry said, referring to Inter's 2009-10 Champions League semi-final victory.
"He's won titles since, but I think he's lost the plot. He believes he has become more important than the team.
"Tactically, I think he doesn't put anything in place. Apart from the players, who have changed, it's the same organisation as last season under Van Gaal.
"He always blames the referee or their opponents' good fortune. There is no self-criticism."