The tennis serve is one of the most important shots of the game. There are many different types of tennis serves players can use, from hard and flat, to angled with sidespin. A good serve is an asset that can alter the tennis ball’s trajectory to drag your opponent way off-court or force a ball to their weakness, giving you a definitive advantage in every game you serve.

The serve starts off every point you play, with players alternating serving each game. Serves can be hit with varying degrees of spin or slice to help the server gain an advantage. The first serve is often a powerful technical shot to set up the point. The better your serve, the weaker your opponent’s return will be. Most players use a serve to try and ace (win the point on a service without the other player making contact with the ball), or catch your opponent on the defensive.

The second serve is for when the server faults on the first attempt—they either step over the baseline (also known as a foot fault), hit the ball out, or hit it into the net. Since servers only get two tries per point unless they hit a “let,” failing to make the serve a second time will lead to a double fault and loss of the point. Both the first and second serves must travel cross-court and land diagonally within the opponent’s opposite service box to count as in play.

The better your serve, the weaker your opponent’s return will be, setting you up to win the point. However, the different types of serves you can use depend on your skill level and the current circumstances in the game.

Flat serve. A flat serve is hard and powerful, making it ideal for a first serve in a tennis game. It is often the fastest serve, hit with a Continental grip (though some professional players like Serena Williams are known to use an Eastern grip). The high speed of a flat serve makes it more likely you’ll catch your opponent off guard, delivering an ace or a defensive return you can quickly put away. However, flat serves also have a few disadvantages. Due to their powerful force, the other player’s return can potentially come back just as equally powerful, which can be disastrous during a game’s key turning points. The flat serve is largely inconsistent, and difficult for shorter players to reach the ball at its highest point to guarantee clearing the net.

Slice serve. The slice serve effectively draws the opposing player out wide to the deuce or ad side, leaving the rest of the court open. The slice serve motion creates sidespin, which can cause the ball to bounce farther away when hit into the outer corner of the service box, or right into your opponent’s body when hit down the “T” (the perpendicular center mark on the court). Slice serves also tend to sit low on the court due to their sidespin and can get your opponent out of position, giving you an opening to take advantage.

Kick serve. The kick serve is a heavy topspin serve, which gives it its signature kick. This type of serve is for more advanced players and takes a lot of practice to master. Kick serves have less power and more control, allowing the server to hit specifically to a player’s weakness (depending on whether they are a righty or lefty). The kick serve is hit high above the net, decreasing the chances of an unforced error, and making them perfect for second serves. When a kick serve hits the ground, it spins forward, forcing the returner back or off to the side. However, kick serves are much slower, which gives the opposing player more reaction time to plan their return.

Underhand serve. Underhand serves are the least commonly used (and most controversial) serve technique in tennis matches. They use a different service motion than traditional serves, with the contact point and follow-through traveling below the shoulder. Underhand serves are mostly taught to children just starting to play, or used by tennis players who have injured their shoulders, backs, or tossing arms and can no longer produce their regular serving motion. Underhand serves fall short and light over the net (like a drop shot), leading the ball to bounce twice before the returning player has a chance to reach it. Competent players who utilize this tactic are sometimes considered “unsportsmanlike.” The strategy is not encouraged in competitive and professional circuits.