John Patrick McEnroe Jr. is an American former professional tennis player. He was ranked as the world No. 1 in men's singles by the Association of Tennis Professionals (ATP) for 170 weeks, and as world No. 1 in men's doubles for 269 weeks. He is one of two male players to have held both No. 1 rankings, and the only one to hold both simultaneously. McEnroe was best known during his playing career for his shot-making and volleying skills, his rivalries with Björn Borg and Jimmy Connors, and his confrontational on-court behavior, which frequently landed him in trouble with umpires and tennis authorities.