On July 4,1970 In the opener of a twin bill between Pittsburgh and Chicago, Roberto Clemente hits his 3rd and 4th Wrigley Field round-trippers in two games. The first blast puts Pittsburgh up, 2 – 1, in the 3rd, and the last provides the Pirates’ final two runs in the 10 – 6 win. With Clemente resting in the second game, the Cubs salvage the split, 7 – 2, behind Milt Pappas, with Pittsburgh falling half a game behind division-leading New York.

Source

Baseball Reference July 4