The Cubs had won eight of 10 going into the final game of a three-game series at Wrigley Field against the Mets, one of four teams (the Expos and Cardinals the others) fighting for the N.L. East title in the summer of 1989.
The Cubs trailed the Expos by 2½ games going into this contest, and the Mets and Cardinals were tied for third, six games back, and had taken the first two of the series, and ran out to a 3-0 lead over the first four innings of this game, thanks in part to a home run by Shawon Dunston.