KANSAS CITY -- A good outing from their starting pitcher and a big inning from their offense is a formula that has worked for nearly two months of the Royals’ season, so why stop now?

Monday was no different.

Michael Wacha allowed just two runs in seven innings, and the Royals put together a six-run sixth inning to beat the Tigers, 8-3, in a series-opening win at Kauffman Stadium.

“Starting pitching, any pitching, to be able to keep us in the game -- we’ve talked about it a million times already,” manager Matt Quatraro said. “Those games are going either way, and then the sixth inning tonight was a big inning for us. Really good at-bats.”

It might not be a million times, but this formula has been talked about many times this season. Because the Royals won their 30th game of the season -- to improve to 11 games over .500 at 30-19 -- like so many others. It was a close, one-run game until the middle innings before the offense took off and put together its signature big inning.

“That’s a starting pitcher’s job, keep our team in it,” Wacha said. “Whenever it’s the second, third time through the lineup, I feel like that’s whenever we start doing some damage. So just try to limit what they’re able to do on the other side, get guys back in the dugout as quick as possible.”

Seeing Tigers starter Reese Olson leave the game early due to a line-drive comebacker hitting his hip in the third inning allowed the Royals to get into the Tigers’ bullpen early. Reliever Beau Brieske didn’t allow a hit for 2 2/3 innings before the Tigers turned to Joey Wentz, who entered the sixth inning having allowed just two earned runs in 16 2/3 innings all year.

He exited after facing five batters without recording an out.

By the time the inning was over, the Royals had scored six runs, five charged to Wentz, and had sent seven batters to the plate before recording an out. It was the Royals’ Major League-leading seventh time scoring at least six runs in a single inning this season.

“I think it stems from being prepared,” second baseman Michael Massey said after going 3-for-4 with his fifth homer of the year being the first Olson allowed this entire season. “Hitting coaches doing a great job, and we’re having a good game plan when we go up there. And then just trying to execute. You get a bunch of guys in a row that execute, and you get those big innings.

“... Get the traffic going, and good things tend to happen. I think we’ll stick with it.”

The bottom of the sixth started with a 10-pitch battle between Wentz and Salvador Perez, who rocketed the 10th pitch he saw 436 feet out to the fountains in left-center for his ninth homer of the year. He hit four consecutive hard fouls toward the Tigers’ dugout at one point, leading several Tigers to point toward fair territory as advice.

Perez took it and didn’t miss.

“Just trying to do my job,” Perez said. “I was late on 3-1, thinking he would throw me a fastball on 3-1. After that, I just tried to make the adjustment. He left a pitch in the middle, and I hit it pretty good.”

The Royals followed with four consecutive hits, a walk to Kyle Isbel, and another hit when the lineup turned over to Maikel Garcia.

When Wacha came out for the seventh inning, he was pitching in a vastly different game. The veteran starter has now put together three consecutive starts of six-plus innings with two earned runs or fewer, posting a 2.37 ERA across those starts with a .176 opponents’ average. He was efficient with 89 pitches (60 strikes) needed across seven innings Monday, walking one and striking out three.

Royals starters have completed at least five innings in 15 consecutive games since May 5 -- a stretch in which they’ve allowed more than two earned runs only twice. This is why the Royals have been so good this year: Their rotation’s 3.06 ERA is fourth-best in baseball.

And their offense finds ways to win despite the questions that surround the outfield production. On Monday, those outfielders came through in the sixth with MJ Melendez’s single and Hunter Renfroe’s two-strike, two-run double.

“I’m telling you, the best teams I’ve played on, it’s the starting pitchers that go out there and go deep and can give the guys a chance to win a ballgame,” Wacha said. “… I feel like we’re just kind of feeding off each other.”