At Busch Stadium, recently acquired Mark McGwire hits his 364th career home run on a pitch thrown by Phillies’ right-hander Mark Leiter for his first National League round-tripper. The Cardinals slugging first baseman will hit a total of 220 homers in the Senior Circuit, all for the Redbirds.

On August 8, 1997 — At Busch Stadium, recently acquired Mark McGwire hits his 364th career home run on a pitch thrown by Phillies’ right-hander Mark Leiter for his first National League round-tripper. The Cardinals slugging first baseman will hit a total of 220 homers in the Senior Circuit, all for the Redbirds.

Source:
Baseball Reference August 8
National Pastime
Retro Sheet
Hall of Fame
SABR Games Project
Replay The Game