It turns out you can teach an old dog new tricks... 

Four shelter dogs rescued from slums and abandoned lots around Sao Paulo were trained as "ball dogs" for the Brazil Open Tournament.

Their job?

To retrieve balls that went out of bounds at an exhibition match, and then give them back to the players.

They didn't like the "giving back" part as much as the "getting the ball" part.

A local shelter hopes to raise awareness with its "ball-dog" initiative.

In case you were wondering, the four dogs were named Frida, Mel, Isabelle and Ostela.