The twist serve was originally known as the "American twist" serve, and it is still sometimes referred to by that name. It is a special kind of topspin-slice serve that behaves differently after the bounce because it has much more topspin than sidespin on it. So, instead of skidding and continuing to curve leftward after the bounce, it "grabs" the court and breaks rightward.
A twist serve is hit with topspin and travels at a lesser pace than the flat serve. The ball travels in a higher arc over the net than a flat serve. It then dips quicker and bounces higher, generally away from the receiving player's backhand. The kick serve in general is safer to hit and is often employed for the second serve. A twist serve is harder to learn, however, because it is hit somewhat behind the head of the server and requires slightly more complex mechanics. It is hit with either a Continental or Eastern backhand grip. The American twist serve is useful for second serves, serve and volley tactics and many other circumstances.
A Twist serve is thrown somewhat behind the server's head, and the racquet brushes the ball from the 8 o'clock position to the 2 'clock position, although more experienced and talented players can have a 7 o'clock to 1 o'clock position, imparting a combination of topspin and sidespin that makes the ball go in an angled arc over the net. Upon bouncing, it jumps high and to the side in the direction of the server's racquet arm. For example, if a right hander hits a Twist serve to the ad (backhand) court, it will jump away from the center of the court.
Due to the partial topspin and height at which it clears the net, the Twist serve has more margin for error than a Flat serve and is sometimes a common choice among top pros for a safe second serve, although some opt to use the "Kick Serve" as a potent first serve option. A player who is able to change the angle at which the racquet brushes the ball (say, 7 o'clock to 12 o'clock) can change the horizontal bounce of the ball at will, reducing the predictability of the bounce for the receiver. Also, because the topspin imparted on the ball forces it to bounce high, the receiver would be unable to hit an ideal shot in their contact zone (typically between waist and shoulder level).
Because the twist serve curves to the receiver's right in the air and then breaks leftward on the bounce, kicking high to (a right-hander's) backhand, this can be the most difficult serve to return.
It is also the most difficult to learn. The contact point is slightly to the left of the server's head and directly over it or perhaps even a little behind it. The required swing path is achieved by an inside angle of attack on the ball. The result is a twisted axis of rotation, so that the ball's spinning is out-of-line with its flight path.
It is possible to hit a twist serve with a Continental grip, but most players and teachers feel that an Eastern backhand grip is necessary.
Like all spin serves, the twist serve travels slower than a flat serve. Servers who follow their serve to the net often take advantage of this fact, hitting the twist serve because it is difficult to return but affords them extra time to get close to the net before the return is back.
Because it has heavy topspin on it, the twist serve is a "safe" serve that can be aimed high over the net and still land in. So it is often used as a second serve. In the anime/manga named "Prince of Tennis", the main character; Ryoma Echizen, uses this move a lot!
