Duffy came into the game with a 2.92 ERA and had pitched eight games this season in which he gave up two runs or fewer. But the Indians peppered him for nine hits and six runs through four-plus innings in the series finale.
"First two innings went by, [and all was well]," Duffy said. "But they started jumping on my fastball. Then, you have to make an adjustment, and I wasn't executing with my offspeed [pitches]. It wasn't a fun day at the park today."
The end of Duffy's day came quickly in the fifth. He was late covering first base on a routine grounder by Brantley, then missed the bag completely with his foot. Two singles later, manager Ned Yost came to get Duffy.
"It was lack of execution in that situation [on Brantley's grounder]," Duffy said. "Any ground ball to the right side we're taught to get over. I was a tick late, tried to over-correct and I ate it.
"You kind of try to make up for the time you lost when you're late. I beelined straight to the bag when [I] normally would take a turn. I went past the bag, over-corrected and tripped over my own feet."
All three of Duffy's runners that inning scored, and suddenly it was 6-1 -- a hole that proved too much for the Royals.
"[Duffy] just wasn't sharp," Yost said. "He was grinding through it. First two runs came on some soft hits. ... But, [it was] just one of those days."
Jeffrey Flanagan has covered the Royals since 1991, and for MLB.com since 2015. Follow him on Twitter @FlannyMLB. This story was not subject to the approval of Major League Baseball or its clubs.