After 5 hours and 49 minutes of play in Pittsburgh, the Pirates’ Jeff King mercifully ends the game with an 18th-inning leadoff home run off the Cubs’ Scott Sanderson. Sanderson had pitched eight innings of shutout relief. The Pirates win, 5 – 4.

This Day In Baseball

On August 6, 1989 — After 5 hours and 49 minutes of play in Pittsburgh, the Pirates’ Jeff King mercifully ends the game with an 18th-inning leadoff home run off the Cubs’ Scott Sanderson. Sanderson had pitched eight innings of shutout relief. The Pirates win, 5 – 4.

Source:
Baseball Reference August 6
National Pastime
Retro Sheet
Hall of Fame
SABR Games Project
Replay The Game