Ron Oester tripled home two runs in a three-run ninth inning to give Cincinnati a split in Montreal.
In the first game, Tim Wallach got his second triple of the game and scored the tie-breaking run on Warren Cromartie's sacrifice fly in the sixth inning. But Andre Dawson's two-run, inside-the-park homer in the eighth proved to be the winning hit.
But the Expos had problems the first game: Jeff Reardon, their top reliever, strained a back muscle in the eighth inning. Reardon has had back spasms since his high-school days, but he said, "This is the worst it's ever felt."
The Expos' left-handed reliever, Woodie Fryman, is still on the 21-day disabled list because of a strained arm muscle.
In the nightcap, Paul Householder singled with one out in the ninth off Ray Burris (0-2), then stole second. Dan Driessen was walked intentionally, then Oester tripled and Alex Trevino singled.
Driessen tied the score 3-3 with a solo homer in the fifth off starter Randy Lerch.
The Expos took a 3-2 lead in the third on Al Oliver's two-run double.
Cesar Cedeno had put the Reds on top with a two-run homer in the first inning, but Montreal got a run back in the bottom of the inning on Dawson's sacrifice fly.