The 2013 Oakland Athletics season was the 45th for the franchise at O.co Coliseum, as well as the 113th in club history. Oakland was defending their division title in the new five-team American League West during the 2013 season. On September 22, 2013, they clinched their second straight American League West championship. They lost to the Detroit Tigers in five games in the 2013 American League Division Series.