“It was a regular Babe Ruthian whack, that four-base bang by Ray in the eighth.” Burt Whitman, Boston Herald, July 20, 1919, p2
Previous earliest use (Dickson Baseball Dictionary, 3rd edition, 2009):
1ST USE. 1920. “A mighty Ruthian clout by Jacobson…tied the score in the ninth” (The New York Times, June 8).