On August 9, 2001 — The Giants score a 6 – 4 victory over the Reds in a game marked by two milestone home runs. Ken Griffey, Jr. hits the 450th of his career, becoming the youngest player in history (by 15 days, over Jimmie Foxx) to reach that mark. He was also the youngest to hit 350 and 400. Barry Bonds hits his 49th of the season, becoming the fastest to ever reach that number.
Source:
Baseball Reference August 9
National Pastime
Retro Sheet
Hall of Fame
SABR Games Project
Replay The Game