"There has to be genuine concern over Manchester United's form and there's a couple of ways to look at why the team that won the title last year is not playing as well this time," Souness told Sky Sports News.
"One theory is that it was a very ordinary Premier League last year. The other is that Sir Alex Ferguson produced miracle after miracle to get that team past the post. I think the truth lies somewhere in between."
The North-West outfit switch their attentions to the Champions League this week as they prepare to take on Shakhtar Donetsk on Wednesday.