When betting on a player's quarterfinal match in a Grand Slam tournament, several key factors should be taken into account: the player's current form and recent performance, including head-to-head statistics against the opponent; surface preference and how their playing style matches up with the specific court conditions; physical and mental fitness, especially after potentially grueling earlier rounds; historical performance in Grand Slam events; and any psychological factors, such as pressure levels and experience in high-stakes matches. Additionally, consider external factors like weather conditions and venue specifics, as these can impact player performance. Analyzing these elements thoroughly can provide valuable insights into the likely outcome of the match.