The Red Devils had to settle for a point in their 3-3 draw with Basel in the Champions League on Tuesday, despite having a two-goal lead.
The 69-year-old boss criticised his team's attitude in the match and believes that they need to up their game this weekend.
"People say our performance on Tuesday was careless and we underestimated our opponents and maybe there's an element of truth in that," said Ferguson. "I certainly wasn't happy, even in the first half I could sense we were too relaxed.
"We have to balance both defence and attack and that's why it's called a team. A team functions in all parts, understanding each other's parts and we're too cavalier at the moment."
The Red Devils host Norwich City at Old Trafford on Saturday.