How a spinner can break the rhythm of the batsman

The key to spin-bowling success is to plan how the ball arrives at the batsman.

If it leaves the bowler's hand hard-spun and dipping, the area of danger the batsman faces is enormous. However, if every ball arrives on much the same trajectory and at the same speed, the area of danger becomes tiny. A good batsman will soon get into his rhythm and think, "Oh, here comes another one, landing in the same spot. Where will I smash it to this time?"

What the bowler needs is to change his pace.