Kansas City, Mo. ? Jeremy Guthrie keeps piecing together solid starts. The Royals keep wasting them.

It happened again Friday night.

Guthrie held the Yankees in check over seven solid innings, his only glaring mistake a three-run double off the bat of Brian McCann. But given the punchless nature of the Kansas City offense, that mistake was all it took in a 4-2 loss in the opener of their four-game series.

“I think I threw the ball all right except for the third inning, when I gave up a couple of hits,” Guthrie said. “I had McCann down to two strikes and couldn’t finish him off.”

The result was a sixth straight loss for Guthrie (2-6), who hasn’t won since beating Tampa Bay on April 9 — a span of 11 starts. In the last five, the veteran right-hander has been given a total of three runs of support while he’s been on the hill.

Salvador Perez and Lorenzo Cain drove in the Royals’ runs.

“We just couldn’t get that big hit to come through,” the Royals’ Billy Butler said. “We were putting some good at-bats together with no results. Those days are kind of frustrating.”

Brian Roberts drove in the other run for the Yankees, who finally gave Chase Whitley (1-0) some support. The young right-hander had allowed five earned runs in his first four starts, and left two of them with the lead, only for his team to receive a series of no-decisions.

Of course, McCann helped to take care of that with his bases-loaded double.

“That’s a huge hit,” Yankees manager Joe Girardi said. “It’s a tough at-bat. He fouls off a lot of tough pitches, a change-up, a curveball, a real slow curveball, and he got a ball up in the zone and it turned into a double.”

Dellin Betances worked around a double by Alcides Escobar in the eighth, and David Robertson retired Perez with runners on first and second in the ninth to earn his 14th save.

Making their only scheduled visit to Kauffman Stadium, the Yankees won their second straight on the heels of a four-game losing streak. They also established some much-needed confidence as they began a 10-game trip that will take them through Seattle and Oakland.

The Royals figured they were catching a break during the four-game series by missing Yankees ace Masahiro Tanaka, who pitched his way to a 2-1 win over the Athletics on Thursday.

Whitley made them wish they were facing the Japanese star.

Mixing his fastball with an effective slider and change-up, the former 15th-round draft pick allowed five hits while striking out three without a walk. He wound up going a career-high seven innings to earn his first major league win.

“Yeah, tonight’s a big night. We’re all happy for him,” McCann said. “He’s worked really hard to get here, to do this.”

The Yankees took a 1-0 lead on a single by Roberts in the second inning, and Kansas City promptly answered when Perez followed a double by Alex Gordon with his own RBI single.

New York quickly regained the lead in the third.

Jacoby Ellsbury and Brett Gardner led off with singles, and Guthrie grazed Mark Teixeira on the shoulder to load the bases with one out. That’s when McCann connected for his double to left, giving the Yankees what turned out to be an insurmountable 4-1 lead.

“He tried to go up and away on McCann, a power-pull hitter,” Royals manager Ned Yost said. “It’s the first ball he’s hit down the left field line all year long. A good piece of hitting by McCann. (Guthrie) did a nice job of holding it from that point on. The three-run third is what ended up getting him.”

NOTES: Yankees SS Derek Jeter got the night off. Asked whether he felt he needed it, he replied: “I never feel like I need a day.” … The Royals traded LHP Justin Marks to Oakland for cash considerations. He was designated for assignment Monday. … New York RHP David Phelps and Royals LHP Danny Duffy are starting Saturday night.