I wanted to pull this find by John Thorn out of the comments section for this post on Luis Padrón (he posted it back on May 12).

FROM: Sporting Life, July 22, 1905:

On the 9th, at Newburgh, Padron of the Poughkeepsie team, gave an
exhibition of batting seldom seen in any game. He went to bat and the
Newburgh rooters began to hurl the epithet of "n*****" at him time and
again. Padron is very dark, being a full-blooded Cuban, but has no
negro blood. This seemed to make him mad, and with two men on bases, he hit the first ball pitched for a
home run. Several innings later he again went to the bat with two men
on bases. The crowd called: "The n***** can’t do it again." At this
Padron hit the first ball pitched for another home run in almost the
identical spot, scoring six runs and winning the game for Poughkeepsie.