A lob in tennis is executed by hitting the ball high and deep into the opponent's court. It can be used as an offensive weapon or a defensive shot depending on the situation.
A lob is usually hit when an opponent is standing near the net, waiting to volley. The ball should sail over the top of the opponent and into the open court behind him. A good offensive lob cannot be reached by the opponent vertically, yet it is low enough and has enough pace so that the opponent can not run back and chase it down. A lob is capable of winning the point outright, although with some risks involved. Topspin greatly enhances the effectiveness of offensive lob but also makes the stroke more difficult. When executing the lob, players usually hit the ball with the racquet at an angle between 0 degrees (flat) and 45 degrees (diagonal). Some players, such as Andre Agassi and Lleyton Hewitt have developed strong offensive lobs.
A defensive lob, on the other hand, simply intends to push the opponent back to the baseline and prolong the point. When a player is pulled out of the court, a defensive lob is also useful to buy time to run back and get into a better defensive position. A lob that is not successful (one which can be reached by the opponent) is susceptible to being smashed. In doubles, spin or slice is generally applied to the lob, so it will go over the head of a player at the net and bounce away from the baseline player.