Roethlisberger completed 25-of-38 pass attempts without an interception.
Emmanuel Sanders also grabbed a scoring pass and Antonio Brown contributed seven catches for 102 yards for Pittsburgh (5-3), which logged its third consecutive win.
Kevin Kolb went 18-of-34 through the air for 272 yards with two TDs and an interception for the Cardinals (1-5), who dropped their fifth straight after winning their season opener.
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