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 or her. A good offensive lob cannot be reached by the opponent, yet it is low enough and has enough pace so that the opponent can not run back and chase it down. It can win 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 at an angle between 0 degrees (flat) and 45 degrees (diagonal). Some players, such as Andre Agassi , Michael Chang , and Lleyton Hewitt , have developed good offensive lobs.