The Sun says ref Howard Webb admitted missing the incident during United's 3-0 win but insisted there was no case to answer after studying video footage yesterday.
A Newcastle source said: "It's unbelievable. If that's not violent conduct what is? Van Persie clearly elbows Yohan.
"It seems as if this is Manchester United getting away with it - again.
"How there has not been a charge over this is incredible."