Player fatigue can significantly impact tennis betting decisions as it influences a player's performance, stamina, and overall mental and physical readiness for a match. When a player has recently participated in a series of demanding matches or has had a long tournament run, they may be more susceptible to making errors and may struggle to maintain their usual level of play. Analyzing factors such as match duration, travel, previous performances, and the player's overall fitness can provide valuable insights into their potential performance. By considering these aspects, bettors can better assess the odds and make informed decisions, especially when a fatigued player is up against a fresh opponent.