The Arizona Diamondbacks, often shortened as the D-backs, are an American professional baseball team based in Phoenix, Arizona. The club competes in Major League Baseball as a member of the National League West division. The team has played every home game in franchise history at Chase Field, formerly known as Bank One Ballpark. The Diamondbacks have won one World Series championship – becoming the fastest expansion team in the Major Leagues to win a championship, which it did in only the fourth season since the franchise's inception. They remain the only professional men's sports team from Arizona to have won a championship title.