On April 29, 1986, in a game against the Seattle Mariners at Fenway Park, Roger Clemens of the Boston Red Sox becomes the first pitcher in Major League Baseball to strike out 20 batters in a nine-inning game. Ten years later, Clemens repeats the feat, the only player in baseball history to do so.

Clemens was drafted in 1983 by the Red Sox as the 19th pick overall and made his debut with the team on May 15, 1984. Two years later, on April 29, the 23-year-old Clemens broke St. Louis Cardinal Steve Carlton’s record of 19 strikeouts in a nine-inning game, which was set in 1969 and duplicated by the Mets’ Tom Seaver in 1970 and the California Angels’ Nolan Ryan in 1974. In 1962, the Washington Senators’ Tom Cheney had 21 strikeouts in 16 innings. Kerry Wood and Randy Johnson each recorded 20-strikeout games after Clemens; however, the “Rocket” as Clemens is known, is the only pitcher in the history of baseball to do so twice. Clemens struck out 20 batters for a second time while pitching for the Red Sox on September 18, 1996, in a game against the Detroit Tigers at Tiger Stadium. He was so fond of striking out batters, he gave each of his four children names that started with the letter K, the symbol for strikeout.

Clemens spent 13 seasons with the Red Sox, during which time he won three Cy Young awards, an annual honor given to the best pitcher in the Major League. He then pitched two seasons with the Toronto Blue Jays and took home the Cy Young award twice more while leading the league both seasons in strikeouts, ERA and wins. Clemens joined the New York Yankees in 1999 and won his first World Series that season. On June 14, 2003, while playing for the Yankees in a game against the St. Louis Cardinals, he recorded his 300th win and 4,000th career strikeout. Clemens was the 21st pitcher in the history of the majors to become a 300-game victor and just the third pitcher (after Steve Carlton and Nolan Ryan) in baseball to rack up 4,000 strikeouts.

In 2004, Clemens moved to the Houston Astros and won his seventh Cy Young award. In 2007, he returned to the Yankees. In December of that same year, Clemens’ name appeared in the Mitchell Report, which alleged he used performance-enhancing drugs during the 1998-2001 seasons. The report, which cited dozens of players along with Clemens, was produced following a 20-month independent investigation by former U.S. Senator George Mitchell into the use of steroids and other performance-enhancers. Clemens immediately denied the allegations.