Wrestlers spend a lot of time learning how to avoid being taken down and how to sprawl. Sprawling means throwing yourself backward and dropping your weight on your opponent's upper body. It is one of the most important standup grappling techniques to learn because it offers you the ability to defend against an assailant's effort to take you down. It is first line of defense in stopping or at least slowing down the opponent's attempt to penetrate and clinch. The second line of defense is to free your legs. And, if the opponent succeeds with a penetration attempt, the third line of defense is to begin the counterattack.
Therefore, to defeat a ground fighter, you must be an effective puncher and kicker, know some effective submission techniques, be an effective standup grappler with good pummeling and sprawling skills, and know some effective ground grappling techniques.