World Series appeared in 9 and won 5. As of 2018, no team has won consecutive World Series championships since the New York Yankees in , , and —the longest such drought in Major League Baseball history. Until the formation of the American Association in 1882 as a second major league, the National Association of Professional Base Ball Players (1871–1875) and then the National League (founded 1876) represented the top level of organized baseball in the United States. All championships were awarded to the team with the best record at the end of the season, without a postseason series being played. From
1989 World Series 9/11-related postponements while the beginning of the 2009 season was postponed due to the World Baseball Classic. The San Francisco Giants won the NL West division by three games over the San Diego Padres, then defeated the Chicago Cubs four games to one in the National League Championship Series. The Oakland Athletics won the AL West division by seven games over the Kansas City Royals, then defeated the Toronto Blue Jays four games to one in the American League Championship Series. It was the Giants' first World Series appearance since , while the Athletics were playing in their second straight