Juan Soto of the New York Yankees strikes out during...

Juan Soto of the New York Yankees strikes out during the ninth inning against the Kansas City Royals at Yankee Stadium on Tuesday. Credit: Jim McIsaac

Marcus Stroman was merely OK – not particularly good or bad, and certainly not delivering the kind of performance that makes him anything close to a lock to be in the Yankees’ postseason rotation.

But Stroman wasn’t the problem Tuesday night.

Seth Lugo was.

The longtime Met, enjoying an All-Star season with the Royals, completely dominated the Yankees over seven scoreless innings, helping send them to a 5-0 loss in front of a lulled-to-sleep crowd of 34,485 at the Stadium.

“That was probably as good a performance against us (by anyone) this year,” Aaron Boone said. “We were silent.”

Lugo, 16-8 with a 2.94 ERA, allowed three hits and struck out 10.

The Yankees (83-62) saw their lead for first place over the Orioles in the American League East cut to a half-game. The Orioles beat the Red Sox, 5-3, in Boston.

After Gleyber Torres led off the first with a single, the Yankees did not get another hit until Torres singled with one out in the seventh, a streak of 17 straight retired.

“That lineup’s relentless, so you don’t ever really get comfortable,” said Lugo, a Met from 2016-22.

The righthander, whom the Yankees hope not to see again this season but very well could as the Royals (80-66) are in the thick of the AL playoff chase, sure looked it while improving to 5-2 with a 2.55 ERA in 14 career appearances (four starts) against the Yankees.

The Yankees, who did not put a runner in scoring position, were outhit, 11-3.

Aaron Judge went 0-for-4 with two strikeouts as his homerless streak was extended to 14 games. He is stuck on 51 home runs.

“He was pounding the strike zone. He was strike 1, strike 2 to most of the guys,” Juan Soto said. “Definitely, it’s tough with a guy who has like nine pitches, and he was showing every pitch today. He was throwing everything (with confidence) and he was keeping us off balance.”

Said Boone: “Looked like he was really dotting it location wise with a big mix. It’s two fastballs, it’s cutter, it’s slider, it’s curveball, it’s change (changeup), and various speeds on all those…I just think it was just hard for everyone to get a bead on him. He’s not making mistakes, it’s hard to really look for one pitch because he’s throwing the kitchen sink at you and he’s changing speeds on it and he’s got a lead and know how to attack with that. He beat us tonight.”

Stroman (10-8, 4.07), coming off a brutal outing in Arlington when he allowed five runs and nine hits over 3 2/3 innings, allowed three runs and seven hits in 5 1/3 innings Tuesday.

“I think it always comes back to mechanics with me,” Stroman said of the improvements made over his start against the Rangers. “I thought my sinker had a better profile today, it was more consistent. That lineup’s really good on the other side. They put together quality ABs, and you feel like they’re just very pesky and they just grind out and do their best to get on base and the run. It’s a tough lineup to deal with.”

Righty Mark Leiter Jr., who took over for Stroman in the sixth, allowed a run in the seventh to make it 4-0, and lefthander Tim Mayza gave up a run in the eighth to make it 5-0.

Royals lefty Kris Bubic took over for Lugo, who threw 105 pitches, in the eighth and struck out two in a perfect inning. Righthander John Schreiber struck out two in a perfect ninth.

The Royals scored twice in the third, getting an RBI single by from Bobby Witt Jr., who is giving Judge a legitimate run for AL MVP, and an RBI single by the ageless Salvador Perez, who followed his four-hit, three-RBI performance Monday with a two-hit, two-RBI effort on Tuesday. Perez’s RBI single in the fifth made it 3-0.

“I thought ‘Stro was all right,” Boone said. “Didn’t give up a ton of hard contact. I like that he was pounding the strike zone for the most part…he got into the sixth inning with three runs, it was just, the way Lugo was going, it seemed like a bigger lead.”

Stroman, a teammate of Lugo’s with the Mets from 2019-21, tipped the proverbial cap.

“Lugo’s been nasty all year,” Stroman said. “Played with him, he’s pretty incredible. He fills it up with a ton of different pitches and he pitches pretty aggressively, so he’s hard to barrel up.”

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