Players use spin to control rallies on clay by incorporating topspin and slice into their shots, which enhances both trajectory and bounce. The slower nature of the clay surface allows for higher bounce, making topspin shots particularly effective as they penetrate deep into the court, pushing opponents back and forcing them into defensive positions. Additionally, slice shots, which remain low and skidding, can disrupt an opponent's rhythm by altering the pace and height of the ball, creating opportunities to exploit openings for aggressive play. By strategically varying the spin on their shots, players can maintain control of the rally, dictate the tempo, and create advantageous positions for finishing points.