Two goals down to a first-half Wayne Rooney double, Manchester City thought they had snatched a point when Pablo Zabaleta followed up Yaya Toure's strike by driving home five minutes from time.
But after Rafael had been fouled on the edge of the area, Van Persie's free-kick flicked off Samir Nasri before cannoning in off the far post.
As United celebrated, Rio Ferdinand was struck by an object which drew blood from a cut close to his eye.
A supporter then ran onto the pitch and had to be restrained by Joe Hart before being carted away by stewards.
- Sports & Recreation
- Pablo Zabaleta
- Yaya Toure
- Samir Nasri