KANSAS CITY — In the fateful seventh inning, the Mets took the lead over the Royals on a 75-mph roller perfectly placed up the middle that scored two runs and broke a tie.

Later in the inning, as the Royals tried to rally with two runners on, a 108-mph screamer wound up a 6-4-3 double play, killing the comeback.

And that is baseball on some nights, as the Mets survived with a 4-1 victory on Saturday at Kauffman Stadium.

“These things always turn around when you get good for some reason,” Royals manager Ned Yost said.

With the score tied at 1-1, Royals starter Jakob Junis was facing the bottom of the Mets lineup in the seventh. He got the first out. But Juan Lagares, hitting .207, then punched a single up the middle.

After that, Aaron Altherr, hitting .074 entering the game, was hit by a pitch, and the Mets rally was on.

“A slider that got away,” Junis said. “That’s one I wanted back.”

Yost opted for right-hander Jake Newberry to face Amed Rosario, and Newberry immediately got ahead 0-2. Newberry’s 2-2 pitch just barely missed, low and inside.

“Man, I thought that was a good pitch,” Newberry said, shaking his head.

Newberry missed again and walked Rosario to load the bases, prompting Yost to go with left-hander Tim Hill, knowing that the Mets would pinch-hit left-handed hitting Joe Panik with righty J.D. Davis.

“The splits weren’t much different [for HIll],” Yost explained.

Hill struck out Davis to set up a battle with Alonso, who at one point in the at-bat blasted one just to the right of the right-field foul pole, so close to being a grand slam that the Mets asked for a crew chief review. It was confirmed foul.

With a 3-2 count, Hill jammed Alonso, who squibbed a grounder through the middle that rolled over the second-base bag. One run scored, but Royals second baseman Whit Merrifield cut the ball off and fired a strike home that appeared on target to nail Altherr.

But Hill curiously cut the throw off, and Altherr scored to make it 3-1.

“Up until the 3-2 count, I was trying to strike him out,” Hill said. “Got to 3-2, just wanted to go with a sinker and get him to hit it on the ground. I got what I wanted.

“But I missed it. I had a chance at [fielding] it. My body was pulling one way and it went the other. I thought it was hit harder than it was. It wasn’t the result I wanted, but I got the ground ball, and weak contact.”

Yost said he wasn’t sure why Hill cut Merrifield’s throw.

“Timmy had no business standing in the middle of the diamond,” Yost said. “His job is to go to a halfway point between third and home plate and watch where the play develops. If the play develops at third, he cuts that way. If the play develops at home, he cuts that way. He doesn’t need to be standing in the middle of the diamond.”

Hill’s explanation: “I was thinking more or less that Whit might have had a play at second and I was stuck in no man’s land. When he threw the ball, I figured it was off-line so I just grabbed it. I’m not sure if it was the best decision at this point. It just happened real fast. It was instinct, and I didn’t want a ball bouncing off the backstop.”

The Royals came back in their half of the inning against right-hander Jacob deGrom when Hunter Dozier and Jorge Soler singled with none out. But Cheslor Cuthbert blasted a one-hopper to short that started a 6-4-3 double play. After a walk to Brett Phillips, deGrom struck out Ryan O’Hearn.

“We’re just not catching many breaks,” Yost said.