CHICAGO (AP) — Jake Arrieta pitched seven strong innings to outduel St. Louis’ John Lackey and lead the Chicago Cubs to a 3-1 victory over the Cardinals on Wednesday night.

Arrieta, coming off a one-hit shutout against Cincinnati last week, limited St. Louis to two hits and an unearned run while striking out 10. He also had a two-run triple in the fourth inning.

The Cardinals, who clinched a playoff berth earlier in the week, remained 1 1/2 games ahead of Pittsburgh in the NL Central. The Pirates lost at Atlanta, reducing St. Louis’ magic number to three for clinching the division title.

The Cardinals’ loss assured NL East champion Washington will open a division series at home.

Lackey gave up two runs and five hits in 6 2-3 innings. He struck out eight, his most since joining the Cardinals at the trade deadline.