KANSAS CITY -- Drew Waters knew the ball was gone as soon as he made contact Monday night. He dropped his bat and watched as it soared 400 feet into the Royals’ bullpen at Kauffman Stadium for his first career home run.

And then he looked for Zack Greinke, thinking only one thing.

“That I just got Zack Greinke’s 100 bucks,” Waters said, laughing.

According to Waters, who told the story after the Royals’ 6-5 loss in 10 innings to the Guardians, Greinke bet Waters shortly after he was called up that the rookie wouldn’t hit a home run for “the rest of the season.”

“I was like, ‘All right, I hope he’s not putting the bad juju on me,’” Waters said. “But as soon as I went deep, that was the one guy I was looking for in the dugout. He actually wasn’t in the dugout, but as soon as he came back in, I was sure to go up to him and tell him he owed me a hundred.”

Greinke hasn’t paid up yet, Waters said, but the veteran pitcher -- who’s slated to come off the IL and start on Wednesday -- did mention the wager when Waters found him in the dugout.

“He was like, ‘That’s awesome, nice swing. I owe you,’” Waters said. “... I’m sure I’ll get a small piece of his fortune.”

Waters’ no-doubt, two-run homer tied the game at 2 in the fifth inning, although that didn’t last long. Royals starter Brady Singer immediately gave up two runs in the sixth inning, continuing what was a back-and-forth affair that the Royals eventually lost on Oscar Gonzalez’s two-run double in the 10th off Carlos Hernández.

Pitching with the automatic runner on second and José Ramírez on first after the Royals intentionally walked the Cleveland slugger, Hernández threw a down-and-away curveball -- where he said he wanted it -- that Gonzalez golfed to the left-center wall.

“You execute a pitch and hope for the best,” manager Mike Matheny said. “You don’t expect the ball to carry like that when you’re making a pitch that’s borderline, and probably was out of the zone. That’s a swing-and-miss pitch. Just unfortunate.”

Regardless of the final result, Waters’ day shouldn’t be overlooked. The 23-year-old was coming off an 0-for-8 stretch with a walk in this past weekend’s series against Detroit after recording three multi-hit efforts over a seven-game span.

Waters has been with the Royals for less than three weeks, and he's experiencing the rollercoaster of emotions and results that many rookies find themselves in when they get to the Majors. That prompted him to have a conversation with senior hitting coordinator Alec Zumwalt before Monday’s game.

“Your first couple weeks here, you want to be -- I wouldn’t say careful, but you don’t want to make mistakes,” Waters said. “I said, ‘I got to be willing to make mistakes. Be willing to swing at a pitch out of the zone, be willing to make an error. Right now, I’m playing too careful.’”

Waters felt -- and saw through video -- that his mechanics were fine, but the results he wanted weren’t there. What changed Monday was the “intent” behind his swing.

“I told [Zumwalt] today, ‘In Omaha, all I was thinking about was hitting homers. I need to do that. Whatever happens, happens,’” Waters said. “And good things ended up happening.”

The outfielder battled McKenzie to lead off the third inning with a double after fouling off three breaking balls in a row. On the fourth, he got a slider over the plate and laced it into right field.

And in the fifth, Waters hammered a first-pitch curveball over the right-field fence. The conversation with Zumwalt pregame seemed to free his mind, knowing he can have a mentality centered around flashing his power rather than focusing on not failing. It reminded him of a lesson he learned from hitting coordinator Drew Saylor when Waters was traded to Kansas City in July.

“Right away, he was talking about why they do a lot of machine work pregame,” Waters said. “One of the things was he wanted us to fail in practice so we learned how to fail and be willing to accept the failure in practice. So when you fail in game-time, it’s not a shot, and you can keep going.”

Waters hadn’t seen whether the Royals found his home run ball yet after Monday’s game; in fact, he’s still waiting on the ball that he recorded his first hit with on Aug. 24. But really, Waters is focused on other things.

“They can keep that one,” Waters said. “I just want the homer. And the hundred.”