— Babe Ruth American baseball player 1895 - 1948
The earliest quotes similar to this are presented as unattributed folk wisdom, such as this example from 1959:
As Brother Allen of Newsweek indicated, it has been fun, but don't try to rest on your laurels. Always remember, “YESTERDAY’S HOME-RUN DOESN’T COUNT IN TODAY’S GAME,” and today’s game is well under way.
The quote does not begin to be attributed to Babe Ruth until the 1980s, nearly 30 years after its first appearance.
Источник: F. N. Abbott, "On Your Marks", in [The Palm, vol lxxix, no. 1 (February 1959), Harry L., Bird (ed.), 1959, Champaign, IL, Alpha Tau Omega, 17, http://hdl.handle.net/2027/uiuc.1744313v0079?urlappend=%3Bseq=19]