Van Persie has starred for United since his move from Arsenal in the summer and Ferguson has admitted that he has been impressed with the Dutch striker's contribution in the club's victories over Stoke City and Braga.
Ferguson said: "Robin's performances are getting better all the time.
"His cross last week for Wayne Rooney's goal was the kind a defender hates, whipped in between the last defender and the goalkeeper. It was brilliant.
"Last week against Stoke, and on Tuesday against Braga, his movement was fantastic. I really was impressed with that, I thought it was really top, top stuff."
Manchester United travel to Stamford Bridge hoping to close the gap on Chelsea to one point in the Premier League table.