A game

American  

Or A-game,

noun

Informal.

1. a person’s best effort, abilities, or achievement.

   The candidate brought her A game to the debate.

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'A' game British  

noun

1. informal one's best possible performance, esp in the phrase to bring or take one's 'A' game

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Etymology

Origin of A game

In reference to a sports contest, with the letter A indicating peak performance

Example Sentences

In a game defined by all-around efficient shooting, USC held on for a 78-75 win over Rutgers Saturday night at Galen Center after nearly surrendering a 19-point lead.

From Los Angeles Times

Another, 17-year-old soccer player Rebin Moradi, called his family as he was leaving a game and told them he was joining a demonstration on his way home.

From The Wall Street Journal

"Normally we have players who finish very well, maybe in a game you miss your chances, but the important thing is that we're generating them."

From Barron's

"Normally we have players who finish very well, maybe in a game you miss your chances, but the important thing is that we're generating them," De Jong told Movistar.

From Barron's

George, who captured Olympic gold with the US team of NBA stars at Rio in 2016, was traded to Oklahoma City in 2017 and led the NBA with 2.2 steals a game in the 2018-19 campaign.

From Barron's