Every year, the tennis calendar delivers one of the most dramatic shifts in all of sports. One day, players are grinding through long rallies on the red clay of Roland Garros. A week later, they are sprinting across slick green grass, reacting to points that can be over in just a few strokes. No transition in tennis happens faster. Clay and grass may both be outdoor surfaces, but they ask players to solve completely different problems. On clay, patience is rewarded. Slow,