Garrett Cooper blasted a home run off Yu Darvish in a two-run seventh and rookie Sixto Sanchez dominated across five innings as the Marlins completed a stunning two-game sweep of the Cubs in the NL Wild Card Series.
With the sweep, the Marlins remained unbeaten in all seven postseason series they have played -- a run that includes wins in the 1997 and 2003 World Series. The Marlins will play the Atlanta Braves in the NL Division Series, which starts Tuesday in Houston.
The Marlins, who lost 105 games in the 2019 campaign, became the first club to reach the postseason following a 100-loss season. Miami finished second in the NL East -- behind the Braves -- with a 31-29 record this season despite early disruptions caused by the coronavirus pandemic.
"The one thing that we talked about all year was why not us? With this kind of pitching, you can do anything," Marlins manager Don Mattingly said. "... You feel like you've got a good shot at kind of stopping almost anybody if you make pitches."
Cooper gave the Marlins a 1-0 lead with two outs in the seventh with a deep drive over the left-field wall. Matt Joyce then doubled to center, and Magneuris Sierra chased Darvish with an RBI single that extended Miami's lead to two runs.
Sanchez overpowered the Cubs, allowing only four hits in his five innings of work. The 22-year-old right-hander walked two and struck out six.
Marlins reliever Brad Boxberger (1-0) threw 1 1/3 innings to pick up the win. Closer Brandon Kintzler gave up a leadoff double to Jason Heyward in the ninth but struck out the next three batters to earn the save.
"I feel like we were competing against the other team and our struggle," Cubs shortstop Javier Baez said. "We couldn't get hot. We couldn't compete and it didn't go our way. We didn't play half of the season and for me the second half is so important. You can make your first half disappear."
Darvish (0-1) allowed two earned runs and five hits in 6 2/3 innings. He had six strikeouts and two walks.
The Marlins will now turn their focus to the Braves in the next round of the playoffs. Miami lost six of their 10 meetings against Atlanta in the regular season, including a 29-9 blowout on Sept. 9.