KANSAS CITY -- Moments prior to his ninth strikeout, Royals starter Brady Singer received a changeup signal from catcher MJ Melendez with two strikes against lefty hitter Gavin Sheets.

Singer obliged. And Sheets swung through it for the second out of the seventh inning, which Singer quickly finished with a groundout.

In his return to the rotation and armed with the confidence to throw his changeup more than he’s done in any of his Major League starts, Singer led the Royals to a 2-1 win on Tuesday night in a doubleheader split with the White Sox, following a 3-0 loss in Game 1 at Kauffman Stadium.

Working in a good rhythm with Melendez -- who proved to be the difference in the nightcap with his first career home run in the sixth inning and excellent tag at the plate in the eighth to keep the Royals’ one-run lead intact -- Singer tossed seven scoreless innings, allowing just four hits with no walks and a career-high nine strikeouts.

To say Singer, who was summoned from a stint with Triple-A Omaha prior to the doubleheader, returned to the Royals’ rotation with an edge would be an understatement.

“That was one of those when they come back and say, ‘I’m going to show you something,’” manager Mike Matheny said. “That’s exactly how you’re supposed to handle this. … He came back with a purpose and looked like a completely different pitcher.”

"Of course. I wanted to go out there and obviously do well -- more for the team than anything," Singer added. "I think the biggest thing was competing. Obviously, I tried to do my best. So I felt really good."

The Royals opened the season with Singer in the bullpen, citing the need for long relievers in case their starters couldn’t go deep into games coming out of the shortened Spring Training. Singer then only pitched in three games (5 2/3 innings), with long rest in between, before he was sent to Triple-A on April 28 to get stretched out.

There, Singer made three starts. He ironed out mechanical issues, fine-tuned the grip on his sinker and mixed in his changeup. He served as the 27th man for Tuesday’s doubleheader, and although the Royals had to send him back to Omaha following the twin bill because of the 26-man roster limit, he likely earned himself another start.

Singer’s efforts did not go unnoticed by Royals coaches, officials and teammates.

“Sometimes people get mad when they get sent down to Triple-A,” said catcher Salvador Perez, who went on the IL with a left thumb sprain between games and watched Game 2 in the trainer’s room. “Sometimes people take advantage of that. … He took it like, ‘How am I going to get better?’ And look what happened tonight.”

Singer threw 16 changeups, which accounted for 17% of his pitch usage (93 pitches total) in Game 2. That’s more than he had thrown previously and it was the biggest positive from a night full of them for the 25-year-old.

Singer’s changeup is his third pitch and crucial to his future success as a starter. He’s shown the ability to dominate lineups with his sinker/slider combination, but in games where one of those two pitches isn’t working, he essentially becomes a one-pitch starter and struggles to get through batting orders multiple times.

The changeup has become the main focus of conversation around his future as a starter -- so much so that his teammates had a little fun after the game with it, hanging the most recent issue of Baseball America above his locker, which conveniently had the word “Changeup!” splashed across the cover.

Even in a game when his sinker/slider combination was dominating and keeping White Sox hitters off-balance, Singer still went to his changeup.

“This could be one of those days that changes his career,” Matheny said. “Being a two-pitch pitcher in this league as a starter is tough. He’s heard about it. We’ve all talked about it to the point of he’s tired of hearing about it. This was something he needed to see for himself, and then he’s going to start figuring it out."

Singer has been working on this pitch since he was selected by Kansas City with the 18th overall pick in the 2018 MLB Draft, with much of that work coming at the Major League level. On Tuesday, Singer went into Game 2 with a clear plan to throw more. The way hitters reacted to his other pitches after he threw a changeup revealed what the third pitch could do.

“Looking at different swings on the other two pitches when I throw it -- it’s been feeling good this whole year, just throwing it more has helped a lot,” Singer said. “Looking forward to a lot more of those outings if the changeup is going to help do that.”

Singer even called to throw it. Facing AJ Pollock with two outs in the second inning, Singer shook off Melendez’s signs for a fastball and a slider to throw a first-pitch changeup, which landed for a called strike and led to a quick strikeout to end the frame with Singer fanning the side.

“It was a big factor,” said Melendez, who became the third Royal in the last 40 years to start behind the plate in both games of a doubleheader. “Him having the confidence in that pitch and being able to use it. It opens up his arsenal, opens up every other pitch.”