FAST thinking Richmond forward Robin Nahas has turned hero, chasing down a thief in the Melbourne suburb of Prahran.

The Tiger goal-sneak was reportedly enjoying coffee with a female friend when a man on a bicycle snatched the friend's bag, with Nahas quickly taking off to dash after him.
 
The chase is believed to have lasted about one kilometre through suburban streets, with Nahas at one stage getting behind the wheel of his car to continue the pursuit.

A member of the public finally knocked the thief off his bike, with Nahas catching up moments later.

The Tiger forward helped apprehend the man and stayed with him until police arrived.

Police told News Limited a 42-year-old man was arrested following the bag-snatch.