The Cardinals gaff the Marlins‚ 5 – 1‚ as Mark McGwire hits his 20th homer of the year. He becomes the fastest player ever to reach 20 homers‚ doing so in his 35th game‚ 6 fewer than Mickey Mantle in 1956 and McGwire himself in 1988.

This Day In Baseball

On May 24, 2000 — The Cardinals gaff the Marlins‚ 5 – 1‚ as Mark McGwire hits his 20th homer of the year. He becomes the fastest player ever to reach 20 homers‚ doing so in his 35th game‚ 6 fewer than Mickey Mantle in 1956 and McGwire himself in 1988.

Source:
Baseball Reference May 24