The Red Devils are currently in eighth place in the Premier League table following Saturday's 1-1 draw with Southampton at Old Trafford.
Neville believes that other teams are now encouraged to attack United when they visit the 'Theatre of Dreams'.
"The key for me is that the speed of their game through the midfield is not quick enough," he told the Daily Mail.
"United have always been about those relentless waves of attacks, sustained for good periods without counter, which would eventually overwhelm the opposition.
"Because this isn't happening opponents have time to rest and recover between attacks, and it means teams are perhaps playing a few more attacking players against United and going into games with a bit more confidence than usual."
United return to Champions League action on Tuesday when they entertain Real Sociedad.