On August 12, 1953 — At Wrigley Field‚ Andy Seminick belts a grand slam in the top of the 9th to break a 6 – 6 tie and give the Reds a 10 – 6 win over the Cubs.

Source:
Baseball Reference August 12
National Pastime
Retro Sheet
Hall of Fame
SABR Games Project
Replay The Game