Andrei Kanchelskis has accused Louis van Gaal of turning his Manchester United players into robots and says he is the wrong manager for the club.
The former United winger, who won two Premier League titles in four years under Sir Alex Ferguson in the 1990s, slammed the Dutchman's methods and said his "strict" approach to matches was in stark contrast to the Scot's.
He is the second former player to criticise Van Gaal recently, after Paul Scholes labelled his style of play as 'too negative'.
"Van Gaal is too pragmatic, his footballers play like robots," Kanchelskis told The Sun. "They are kept within a strict framework, they are not allowed to improvise contrary to what Ferguson allowed us to do.
"Van Gaal, of course, is a good coach, but in my opinion he is not for Manchester United. Their history and tradition is to play wide and be sharp at the flanks - but there is nothing like this now.
"I'm looking at his game for the second season now. He says that the transformation is going on, but I still couldn't understand what he is looking for. There is an impression that he doesn't know what he wants. No creative players, no wingers. Nobody could serve Wayne Rooney.
"The current Manchester is not the same as it was under Ferguson."
United host CSKA Moscow in the Champions League on Tuesday evening having secured a 1-1 draw in Russia last month, but Kanchelskis said he was shocked at United's first-half performance in that game.
"The first game against CSKA showed that it is possible to win against this team," he said. "I was at the stadium and I was surprised how disgustingly United played in the first half. A lot of ball control but no sharpness at all.
"In the second half it got better because of the substitution of Bastian Schweinsteiger, who was slowing the game down. I guess, Manchester United is not his team."
The 46-year-old also claimed that United had goalkeeper David de Gea to thank for their start to the season, while criticising Van Gaal for letting fellow-Dutchman Robin van Persie move to Fenerbahce in the summer.
"They were saved with the fact that De Gea stayed in the team," Kanchelskis said. "If he had left, Man United would have done much worse. He is a very strong goalkeeper, he saves the team a lot."
On Van Persie, he added: "Let's say, he did not have a good season. But nobody shone until the end of the season from those who played in Brazil at the World Cup last year.
"Even Lionel Messi was exhausted, as well as the Germans. How could you let go of such a player?"