The term 'PARTS OF TENNIS MATCHES' can be broken down into four crossword solutions: SETS (4 letters). In tennis, a set is a sequence of games played with service alternating between players. A set consists of at least six games, and the winner is the first to win six games with a two-game lead. Sets are typically played in best-of-three or best-of-five formats, with the exception of Grand Slam tournaments, which use a best-of-five format for men's singles and doubles and a best-of-three format for women's singles and doubles.