United are currently top of the Premiership having only lost out to Wolves in the league this term but Ferguson admits the competition is becoming tough.
The Scottish tactician is therefore disappointed with the criticism of his side and says they have done well in the face of tough challenges.
"People have not stopped criticising us. It's as if we don't play well," he said in French newspaper L'Equipe.
"But at home we have been fantastic. Away from home it is different.
"Any team now believes they have a chance against the big clubs. That was not necessarily the case five or six years ago. We are in danger anywhere."
Ferguson hailed the determination and winning mentality at Old Trafford and admits there is a 'family' feel to the squad.
He added: "Our current group refuses defeat. We never give up. I rely on players like (Ryan) Giggs and (Paul) Scholes to bring those values, but also ones who have been here five or six years.
"(Patrice) Evra, (Rio) Ferdinand, (Nemanja) Vidic, (Edwin) Van der Sar, (Michael) Carrick belong to the same family. That is why we are not easy to beat.
"I don't know many teams in the world with such determination."