Tom Cheney of the Washington Senators struck out 21 batters in a single game in 1962. Cheney struck out 13 through nine innings and finished with 21 in his 16-inning complete game, a 2-1 victory over the Baltimore Orioles.
As of April 2014, Roger Clemens (1986 and 1996) and Kerry Wood (1998) are tied for the most strikeouts in a nine-inning game with 20. Randy Johnson also struck out 20 in a 2001 game, though that contest went to extra innings. A total of seven pitchers have tallied exactly 19 strikeouts in a nine-inning game, including all-time leader Nolan Ryan.