Wainwright hit the 20-win mark for the second time while matching his career-high for victories, and the Cardinals moved a step closer toward their second straight division title.
They remained 2 1/2 games ahead of Pittsburgh in the NL Central with five to play with the Pirates beating Atlanta 1-0. St. Louis clinched its fourth straight playoff appearance on Sunday.
Wainwright (20-9) won his fifth straight start and made it look easy, striking out eight and walking one.
The only other time Wainwright won 20 was in 2010, and that year, victory No. 20 also came at Wrigley Field.
He got plenty of support, with the Cardinals pounding Travis Wood (8-13) for seven runs and eight hits over five innings.
