After six- and eight-run outbursts in wins over St. Louis on Monday and Tuesday, the Royals (29-32) have tallied seven over their last three. Friday's 4-2 series-opening defeat came despite four doubles.
"We just couldn't get that big hit to come through," said Billy Butler, who was 1 for 4 but is batting a career-low .261 with runners in scoring position. "We were putting some good at-bats together with no results. Those days are kind of frustrating."
Kansas City is 13-15 since May 8, scoring three runs or fewer in 13 of those losses. They're 5-28 when scoring three or less compared to 24-4 when they manage at least four runs.
Duffy (3-5, 3.05 ERA) has grown accustomed to a lack of run support, as the three runs he received his last time out matched the total from his previous seven appearances spanning 27 innings.
"Sometimes it's just the luck of the draw," Duffy said.
The left-hander gave up just one hit over six innings in Monday's 6-0 victory at St. Louis.
Opponents' .190 batting average versus Duffy is the fourth-lowest among American League pitchers with at least five starts.
Duffy was crushed by the Yankees as a rookie, allowing eight runs and eight hits in three innings of a 9-7 loss on Aug. 16, 2011. He picked up a victory in his second meeting, however, limiting them to two runs over 5 1-3 innings in a 4-3 win on May 3, 2012.
The Yankees have won eight of their last 10 versus the Royals and six of seven at Kansas City. New York's offense hasn't exactly been producing either, as the Yankees (31-29) had totaled 16 runs while losing five of seven.
But Brian McCann's three-run double in the third was more than enough, and Dellin Betances and David Robertson each threw a scoreless inning in relief of winner Chase Whitley. New York also got three scoreless innings from its bullpen in Thursday's win over Oakland after it had allowed four or more runs in each leg of a four-game skid.
Jacoby Ellsbury is 17 for 44 (.386) during an 11-game hitting streak, and he's batting .406 over his last 22 matchups with Kansas City with 21 runs scored.
New York starter David Phelps (1-3, 4.11) is looking to shake off a rough outing after yielding six runs - the second-most of his career - over six innings in a 10-2 loss to Seattle on Monday.
Phelps lost to Duffy in his only previous game versus Kansas City, allowing two runs in four innings.
Alex Gordon is batting .385 with 17 RBIs over his last 19 contests, raising his average 39 points to .289.
Derek Jeter received an off-day Friday but is 23 for 50 with 11 runs scored and nine driven in over his last 11 games versus the Royals and batting .328 against them for his career. He's also 3 for 6 with two doubles off Duffy.