Kendrys Morales went 4 for 4 and drove in two runs, and Eric Hosmer also had a pair of RBIs as the Royals roughed up Adam Wainwright (6-5) to snap a four-game losing streak to their cross-state rival.
Duffy (3-1) served up a two-run homer to Matt Holliday in the first before settling into a nice rhythm, keeping the Cardinals off balance with pinpoint control. The left-hander struck out eight and didn't walk a batter while breezing through a lineup that scored 11 runs the previous day against Seattle.
