This drill teaches the players the importance of momentum and concentration
until the end.
a) Two players play and the game starts with a serve.
b) The score is only one (not X:Y but just X) and it starts
at 0
c) The server's winning points increase the score by +1,
and the returner's winning points decrease the score by 1. Example:
if the server wins first two points, the score is 2. If then the
returner wins one point, the score goes to 1.
d) The first player to reach +3 or 3 wins the game. Then
they change roles  the server now returns and vice versa.
e) The whole score is now 1:0 and they play to 3. So the
winner wins by 3:0, 3:1 or 3:2.
Benefits:
 Players learn to fight and never give up, even when things don't
look so well. They can get back in the game faster. Example: if
the opponent leads 2:0 and you win 1 point, you've actually pulled
your opponent away from winning the game.
 In real tennis when your opponent is 40:15 up and you win a
point, he can still win the game with the next point. But that
is only on the score board. Psychologically the leading player
feels as if he is held back and can become impatient. And you
know what that means.
 The player also learns to focus and fight for the last point,
even if he leads 2:0. If he loses the point, he will now need
2 in a row to win the game. In reality most players relax too
much when they lead 40:0. This gives good players a chance to
catch up.
