Juan Marichal, pitcher for the San Francisco Giants, strikes John Roseboro, catcher for the Los Angeles Dodgers, on the head with a bat, sparking a 14-minute brawl, one of the most violent on-field incidents in sports history.

Juan Antonio Marichal Sánchez, nicknamed "the Dominican Dandy", is a Dominican former right-handed pitcher who played 16 seasons in Major League Baseball from 1960 to 1975, mostly with the San Francisco Giants. Known for his high leg kick, variety of pitches, arm angles and deliveries, pinpoint control, and durability, Marichal won 18 games to help the Giants reach the 1962 World Series, and went on to earn 191 victories in the 1960s, the most of any major league pitcher. He won over 20 games six times, on each occasion posting an earned run average (ERA) below 2.50 and striking out more than 200 batters, and became the first right-hander since Bob Feller to win 25 games three times; his 26 wins in 1968 remain a franchise record.

The 1965 San Francisco Giants season was the Giants' 83rd year in Major League Baseball, their eighth year in San Francisco since their move from New York following the 1957 season, and their sixth at Candlestick Park. The team finished in second place in the National League with a 95–67 record, 2 games behind the Los Angeles Dodgers.

John Junior Roseboro was an American professional baseball player and coach. He played as a catcher in Major League Baseball from 1957 until 1970, most prominently as a member of the Los Angeles Dodgers. A four-time All-Star player, Roseboro is considered one of the best defensive catchers of the 1960s, winning two Gold Glove Awards. He was the Dodgers' starting catcher in four World Series with the Dodgers winning three of those.

The 1965 Los Angeles Dodgers finished the regular-season with a 97–65 record, which earned them the NL pennant by two games over their arch-rivals, the San Francisco Giants. The Dodgers went on to win the World Series in seven games over the Minnesota Twins.