NEW YORK — The loud-mouthed Yankees fan sitting in the second deck behind home plate Wednesday night at Yankee Stadium repeatedly screamed at plate umpire Angel Hernandez during the eighth inning.

All the man wanted was for Seattle Mariners rookie left-hander Yusei Kikuchi’s cap to be checked.

Later in the inning, a handful of fans sitting in the same section chanted for a hat check.

By then, there were tweets of Kikuchi being caught on television with the inside of his bill caked with a foreign substance that resembled pine tar.

The umpires did nothing, the Yankees either weren’t aware or opted to do nothing and Kikuchi ended up pitching into the eighth after flirting with a no-hitter in a 10-1 Mariners rout.

“I was aware of it very late,” Yankees manager Aaron Boone said. “I was made aware of it sometime in the eighth inning there, so I’ll take a look at it and we’ll kind of see what we make of it.”

It’s possible that the Yankees found out earlier and they opted to ignore the cheating because many pitchers – including most of theirs, probably – use something illegal to get a better grip on the ball.

“A lot of guys use stuff,” Yankees first baseman Luke Voit said.

The pine tar on Kikuchi’s cap, however, wasn’t just a little spot. The entire inside bill was covered, and this foreign substance perhaps contributed to the Japanese pitcher no-hitting the Yankees for 5 1/3 innings on his way to a one-run, two-hit, 7 2/3-inning masterpiece.

“It’s frustrating obviously because maybe then his curveball wouldn’t have been as good,” Voit added. “He might have made more mistakes with his fastball. But at the end of the day he had a no-hitter into the sixth inning.”

All of the Yankees hitters who talked to media after the game talked up Kikuchi for locating all of his pitches – including 92-94 mph fastballs - with a very slow delivery.

Here’s more from Voit:

“He’s different. You have to get used to the stutter (delivery). A lot of first-pitch curveballs. We saw a lot of fastballs off his slider and his curveball. He didn’t really make any mistakes.”

Catcher Austin Romine was complimentary, too.

“He put together a good start and went deep in the game,” Romine said. “He didn’t give us too much to hit. He was pounding balls in, throwing backdoor sliders to righties. When you’ve got a guy commanding all the pitches he’s got all over the place, it’s tough to scrap some hits together off of him.”

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Romine claimed he was unaware of the commotion about Kikucki’s cap until it came up in his post-game interview.

“I was too busy trying to figure out how to stop giving up runs,” Romine said. “He had stuff on his hat? That’s not my zone. I don’t talk about that kind of stuff. There are other people that take care of that.”

But Kikucki may have been cheating the whole game.

“I could care less,” left fielder Cameron Maybin said. “Nobody noticed it, nobody said anything. We’ve got a lot bigger worries, trying to manufacture runs, trying to get on base, but I don’t think that had anything to do with it.”

Randy Miller may be reached at rmiller@njadvancemedia.com. Follow him on Twitter @RandyJMiller. Find NJ.com on Facebook.