Dutch great Ruud Gullit says Erik ten Hag must realise the differences between Dutch and English football at Manchester United.
Gullit says his compatriot must adapt quickly to English football if he is to succeed as manager of the Red Devils.
"If you come with a Dutch mentality to England, it's difficult," Gullit explained in an interview at the Laureus Academy.
"You have to adapt. You have to understand that you don't win games with football alone, you also need strength and energy.
"There are a lot of problems at Manchester United, I think they have missed the opportunity to change their football.
"They live too much in the past. They talk too much about the team of the 1990s."
On the other hand, he believes Cristiano Ronaldo regrets returning to Manchester United.
"That's my feeling. He doesn't say it, but I think he regrets it because of the team that was there." he continued.
"I think he expected the performance to be better, so he will want to show everyone who criticised him at Manchester United how much he is still worth.
"I think he has that mission."
