The United striker has revealed where his side need improvement.
Indeed, the Dutchman believes Louis van Gaal's side's mistakes are actually originating further up the pitch, which in turns hinders their back line when teams attack them.
United spent heavily on attacking reinforcements this summer but their lack of defensive depth has left them with just one fit centre-back this weekend.
And those attacking reinforcements, the likes of Radamel Falcao, Angel Di Maria and more - as well as United's existing front men, Wayne Rooney, Juan Mata and co - are not doing their job tracking back, according to Van Persie.
The 31-year-old believes errors at the back are created by 'a mistake before the mistake.'
“When you look at the defensive mistakes, it starts somewhere else," he told Fox Sports News.
"That's where we looked at as well. It's not just the one mistake which happens. There's a mistake before the mistake and before the mistake, maybe positional wise. That's where we looked at.
"Everyone knows where we have to improve."
Man United lost 5-3 at Leicester City last weekend after surrendering a 3-1 lead and will hope to bounce back at Old Trafford on Saturday afternoon, when they host Sam Allardyce's West Ham United.