On July 2, 2002 The Giants score eight runs in the 1st inning on their way to an 18 – 5 rout of the Rockies. OF Tsuyoshi Shinjo gets five hits for San Francisco, including a double and two home runs. Damon Minor, Shinjo, and Reggie Sanders each homer twice to tie a major league record. The Giants become the 16th team to have three players with multiple home runs in the same game.

 

Source:

Baseball Reference July 2