In the first game of a doubleheader with the Washington Senators, St. Louis Browns rookie George Sisler goes all the way, allowing 6 hits in winning, 5 – 2.

On July 15, 1915 In the first game of a doubleheader with the Washington Senators, St. Louis Browns rookie George Sisler goes all the way, allowing 6 hits in winning, 5 – 2.

Source
Baseball Reference July 15