KANSAS CITY, Mo. — If you want to harp about how awful the Royals are and downplay Sonny Gray’s best effort as a Yankee, go ahead.

Yet, Gray and the Yankees don’t pick and choose whom the right-hander faces during the course of a season. MLB sets the schedule and teams abide by it.

And remember this: Gray wasn’t very good against another bad team, the A’s, in his previous start.

So, to dismiss Gray’s dominating performance Sunday because it was against the Royals in the Yankees’ 10-1 mauling in front of 24,121 at Kauffman Stadium would be foolish.

“It was rhythm,’’ Gray said of the reason he gave up one run and four hits in eight frames to even his record at 3-3 and shrink his ERA to 5.48. Of his 20 regular-season starts as a Yankee, this was easily his best.

“Just stay on top of the rubber and make a good pitch,’’ he said.

Gray didn’t allow a hit until Hunter Dozier dropped a two-out, bloop single into center field. It wasn’t until the eighth that the Royals scored a run and ruined any chance the right-hander was going to start the ninth.

“His stuff was great, the slider was a really good pitch for him,’’ Aaron Boone said. “He was on the attack all day. He was electric.’’

So, too, were the Yankees’ bats. One game after feasting on Danny Duffy, the Yankees blitzed lefty Eric Skoglund and then tattooed a pair of relievers.

With his playing time expected to be slashed when Greg Bird returns from the disabled list (possibly this week), Tyler Austin hit two of the Yankees’ four homers. The first traveled 440 feet to left field and highlighted a three-run fourth inning. The second was to dead center and upped his season total to eight. That’s four behind team leader Gary Sanchez.

“I take it day by day and stay with my approach,’’ Austin said of his four-RBI day.

Miguel Andujar and Austin Romine (3-for-5, two RBIs) hit back-to-back homers in the ninth against Jason Adams to complete the beating of the Royals, who are 14-32.

The Yankees’ 21st victory in 25 games allowed them to leave Missouri with two out of three wins, raised the best record in baseball to 30-13 and kept them tied with the Red Sox for the AL East lead.

It also continued a positive trend of winning games against teams that aren’t very good. The Yankees are 16-8 against clubs that started Sunday’s action at .500 or worse.

One glowing start against a bad team doesn’t mean Gray is about to morph into the dependable third starter the Yankees believed he would be when they acquired him from the A’s in July. However, if he can get ahead early in the count — as he did Sunday — Gray has a chance to be a lot better than he has been so far.

“When he is ahead he has the weapons to put people away,’’ Boone said of Gray, who pitched with eight days’ rest due to off days and rainouts. “That was clear today and the stuff is elite. That is why we were so optimistic about him even when he was going through some struggles.’’

Romine, who has become Gray’s personal catcher, didn’t have to think long for the reason Gray dominated.

“The biggest thing today was he threw the slider and curveball for strike one,’’ Romine said.

Scoff at Gray’s gem against the Royals but entering Sunday’s action KC’s .259 team batting average was fourth among AL teams and five points better than the Yankees.

Does it mean Gray is ready to string dominating performances together? No. But it does show what he is capable and provides the Yankees with hope.

“Hopefully, it is something he builds on the next time out,’’ Boone said.