“A” Game

An “A” game is a player’s best efforts, the very top of his or her game. A player who plays very well is said to have brought his or her “A” game to the contest.
 
The term “‘A’ game” has been cited in print since at least 1991, when it was used in the sport of golf.
 
   
5 June 1991, Modesto (CA) Bee, “Mickelson, Wentworth go head-to-head today” by Ron Agostini, pg. C-4:
Evidence is strong Mickelson has not brought his “A” game to Poppy Hills, the Northern California Golf Association flagship course tucked into the Del Monte Forest.
 
13 June 1991, Chicago (IL) Sun-Times, “Winning not foreign to Ballesteros” by Len Ziehm, pg. 98:
But he brought his “A” game here, as evidenced by his finishes the last seven weeks.
 
28 August 1994, Augusta (GA) Chronicle, “Lowery fashions second straight 66” by Bob Green (Associated Press), pg. 8B, col. 1:
“I have a lot of respect for the players playing in this tournament, but I know if I play my ‘A’ game, I can play with these guys,” Lowery said.
 
15 May 1995, San Antonio (TX) Express-News, “Spurs take command - Punishing defense puts Los Angeles in 3-1 hole” by Glenn Rogers:
“We just want every player to bring his A-game.”
 
23 February 1997, Chicago (IL) Sun-Times, “Notre Dame keeps NIT hopes alive” by Daryl Van Schouwen, pg. 13:
“But a lot of people brought their `A’ games today.”
 
Google Books
The Student-Athlete Survival Guide
By Marc Isenberg and Rick Rhoads
Camden, ME; London: Ragged Mountain
2000
Pg. 2:
Toronto Raptor star Vince Carter said, “I’m going to have to step up and play because Grant Hill is going to bring his A-game.” A -game is used so frequently in sports to refer to top performance that it has become a cliche.
   
National Review Online—The Corner
Carville: ‘President Didn’t Bring His A-Game’
By Nathaniel Botwinick
October 3, 2012 11:30 P.M.
James Carville bemoans Obama’s poor performance tonight: ...
(Referring to President Barack Obama’s debate performance—ed.)