The Chicago Cubs defeated the St Louis Cardinals 5-1 to clinch their second consecutive National League (NL) Central title on Wednesday.
It was the third time in franchise history that the Cubs clinched a play-off spot on a day they were playing in St Louis.
They will now make a third straight postseason appearance for the first time since 1906-08.
The Cubs snapped their World Series drought in 2016 by defeating the Cleveland Indians in seven games.
With 12 wins in their last 15 games, the Cubs will enter the postseason in great form.
John Lackey allowed just one run in six innings Wednesday to move to 12-11 this season.
Chicago will play the Washington Nationals in the NL Division Series.
Washington will host the first two games in the best-of-five series. It will then host game five if required.