The centre-back’s attempted clearance struck the Dutchman, who was on the ground following a challenge, with the whistle having already been blown.
Williams was booked for his part in the incident, but Ferguson believes he deserves greater punishment for his “deliberate” act:
“I think the FA has got to look into it. Irrespective of him having a yellow card he should be banned for a long, long time.” The Scot told Sky Sports after the game.
“It’s the most dangerous thing I’ve seen on a football field for many, many years.
“(It was) absolutely deliberate. The whistle’s gone, the game has stopped and he’s done that a foot from the player.
Fergie went on to suggest that van Persie was lucky to escape without injury:
“He could have killed the lad – it’s a disgraceful act and he should be banned for a long, long time.”
Williams played down the incident, claiming that it was purely accidental:
“I tried to clear the ball it hit him on the head. I was trying to clear the ball. He was obviously a bit angry about that. It was a much ado about nothing.”
United took the lead through Patrice Evra, before Michu levelled with a close range finish.