“Now came the 8th, the dreadful 8th, of which the Eurekas had such fear. Charlie Smith led off with a nice hit to left field.” “Atlantic vs. Eureka–Another Exciting Contest–the Atlantic Still Champion–Game 21 to 20,” Brooklyn Eagle, August 19, 1865, p2
Previous earliest use (Dickson Baseball Dictionary, 3rd edition, 2009):
1874. (New York Sun, July 3; Edward J. Nichols).