A match played between two players, one on each side of the court. Singles uses the inner sidelines (excluding the tramlines). It's the marquee format of professional tennis. Grand Slam singles titles are the ultimate measure of a player's career. The court feels enormous when it's just you out there, which is partly why tennis is considered one of the most mentally demanding individual sports.
"Singles final on Centre Court. Two players, no teammates, no substitutions. Just you and the other side of the net."