Nice comments guys.
Heres my opinion (if your an attacking player)
1) When receiving serve, always think in your head the ball is coming long
2) In this case a backspin serve.
3) Now, hunt for the ball.. watch the ball, its speed and the contact the opponent put on the bat. If you feel its coming long your then ready to topspin it with your bh or fh.
4) Now, if the backspin serve comes short, your are ready to move into the table and push the ball short or push long. Have the angle of your bat turnt and push the ball.
Good luck, if you type in pingskills in youtube, there should be some videos on pushing and receiving serves
Good luck