On July 18, 1969 — At Crosley Field, the Astros take a 9 – 0 lead after batting in the 6th, only to lose, 10 – 9. The Reds score a run in the 6th, two in the 7th, and tie it with six in the 8th. Cincy wins it in the 11th when Ted Savage drives in a run off Jack Billingham.
Source:
Baseball Reference July 18