KANSAS CITY -- On Aug. 11, 2023, Adam Frazier struck out swinging against his former Seattle teammate, Luis Castillo, on a slider down and in, leading to a bewildered swing from the then-Orioles utilityman.

Now with the Royals, Frazier entered Saturday’s matchup against Castillo and the Mariners thinking about that slider and how Castillo would use it with his fastball and changeup to attack him. Frazier saw all of them multiple times in his at-bat in the second inning of the Royals’ eventual 8-4 win at Kauffman Stadium that gave them a series victory.

In a nine-pitch at-bat, Frazier fouled off six consecutive pitches. He took a called strike and then a ball in the first two pitches, then fouled off a changeup and fastball.

“I think he’s thrown one slider to a lefty the past couple of games,” Frazier said. “He struck me out on one last year with the slider, which was the last thing I was looking for, so coming into today, I had a feeling he might use it at some point.”

Pitch No. 5 brought that first slider, at the bottom of the strike zone. Frazier fouled it away. He did the same to a fastball up, then again to another slider down. A changeup down and away was the sixth and final pitch Frazier hit foul, hoping it would lead Castillo to go back to the heater.

It did. An elevated, 95.8 mph fastball came at Frazier, who drove it out over the right field fence for his second home run of the year.

“It’s just a cat and mouse game,” Frazier said. “You fight until you get a pitch.”

Frazier homered and doubled in Saturday’s win that saw the Royals’ offensive resiliency in a different way than Friday’s massive comeback win. Every time the Mariners (36-30) scored in the top of an inning, the Royals (39-26) punched back harder in the bottom frame.

After a first-pitch leadoff homer from J.P. Crawford in the first inning off starter Alec Marsh (5-3), who ended up allowing four runs in five innings with eight strikeouts, the Royals answered with a run of their own on Salvador Perez’s RBI single.

After the Mariners scored two in the top of the fifth to take the lead, the Royals fought back with a three-run frame, started by Frazier’s leadoff double and Nick Loftin’s RBI single. Vinnie Pasquantino’s 18th double of the year added two more runs.

The Royals scored a season-high five runs off Mariners starter Luis Castillo, who entered Saturday with a 2.99 ERA.

“We know how good he is, the whole league knows how good he is, and how good he has been,” manager Matt Quatraro said. “But put the pressure on him. No easy outs. … They competed really well and had a good plan. And they stuck to it.”

After the Mariners scored one run in the top of the sixth, Royals center fielder Kyle Isbel delivered in a left-on-left matchup against Mariners reliever Kirby Snead, knocking a two-out, two-run double to left field.

The bottom of the lineup came through Saturday, with five runs scored and five RBIs from the bottom three in the order.

That included Hunter Renfroe’s double in the eighth inning after pinch-hitting for Frazier back in the sixth. Dairon Blanco pinch-ran, stole third base and scored a run.

“How often do you see a guy hit a homer and double and then get taken out?” Pasquantino said. “Baseball, right? And then the next guy hits the double. That seven-hole was hot today. That’s what we like to see.”

The Royals have scored 18 runs off one of the American League’s best pitching staffs in the last two games and are seeing more production from hitters at the bottom of the order as they find their stride.

Frazier, for example, batted just .164 over his first 29 games to start the season. But over his last 20 games since May 8, he’s batting .309 (17-for-55). He’s given the Royals’ tough, relentless at-bats, like the nine-pitch homer Saturday. The reason the Royals signed Frazier this offseason is because of that approach, and the adjustments he’s made mechanically with his swing recently are leading to results.

Frazier lowered his hands and brought them closer to be able to drive inside pitches more. He’s tried to shorten his swing and use the whole field in his pregame work and in games.

“It’s a long season,” Frazier said. “It’s day to day. It’s a lot of ‘feels,’ and ideally, you’d be able to keep the same feel for 162 games, but that’s not really realistic. It’s just hard work, get to a routine that works.”