Arizona Diamondbacks | 45,609 followers on LinkedIn. Official LinkedIn for the Arizona Diamondbacks. | The Arizona Diamondbacks have won five National League West Division Championships (1999, 2001-02, 2007, 2011) since entering Major League Baseball as an expansion franchise in 1998. The D-backs also became the fastest expansion team to win a World Series Championship after defeating the New York Yankees in the 2001 World Series in only their fourth year of existence. The club plays its games at Chase Field in downtown Phoenix, which features a signature swimming pool and a retractable roof, to keep fans comfortable in an air-conditioned facility during the hot summer months.