noun
opening game
Refers to the first game of a sports season, tournament, or series. A straightforward loanword from English.
明日はプロ野球のオープニングゲームだ。
Tomorrow is the opening game of the professional baseball season.
Variant with interpunct; less common in running text.
開幕戦 is a native Japanese compound also meaning 'opening game', often used interchangeably with オープニングゲーム in sports contexts. オープニングゲーム is a direct loanword and may sound slightly more modern or casual.
Loanword from English 'opening game'.