HOUSTON -- Joel Payamps had runners on second and third and no outs in the bottom of the 10th inning Wednesday afternoon when Astros center fielder Jake Meyers lined a 97.7 mph ball back to the mound.

The Royals reliever chased the ball toward first base after it hit him in his right leg, throwing to first for the out.

The only problem was, that out didn’t matter. Alex Bregman came home to score the winning run on the groundout, handing Kansas City a 6-5 walk-off loss in extra innings at Minute Maid Park.

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Payamps (0-3) didn’t have a play at home with Bregman running on contact, but it didn’t help that he threw to first base rather than home on the final play of the game.

“I think after the ball hit him, it was just a panic more than anything else,” manager Mike Matheny said. “It doesn’t matter if there’s not a play, you almost have to throw it there anyhow in that situation. It’s an odd spot for anybody to be in, and then once it hit him, it just magnified that spot.”

Payamps was in the game in the 10th after Houston came back against Kansas City's bullpen.

The Royals have faced the Astros seven times over the past 10 days, and the bullpen held one of the best offenses in baseball quiet for six of those games. The unit entered the series finale having posted a 1.89 ERA (four earned runs in 19 innings) against the American League West leaders.

On Wednesday, the Astros finally got to the Royals' relievers.

After six strong innings from starter Mike Minor, who allowed three runs on six hits and one walk with three strikeouts, the Royals took the lead on Whit Merrifield’s first-pitch grand slam in the seventh off reliever Cristian Javier, who took over for Lance McCullers Jr. with two outs. It was Merrifield’s first home run since June 29 against Boston -- 194 at-bats ago -- and he deposited it into the Crawford Boxes in left field before the silent crowd threw the ball back onto the field.

“Whit with the big hit kind of shifted momentum in our dugout,” Minor said. “With the way the game was going, it was kind of dead in there. We just had to finish it out, and we couldn’t do it. They’re a good offense over there, good team, and we couldn’t hang on.”

The Astros came back against Domingo Tapia with a run in the bottom of the seventh. Josh Staumont took over in the eighth and put two men on with a walk and a single. Staumont got two outs, but with Michael Brantley pinch-hitting, Matheny went to Scott Barlow, the Royals’ most reliable reliever.

Brantley lined a fastball up the middle to drive in the tying run.

“He’s in a tough bind right there,” Matheny said. “You got one of the best hitters in the league, and we got the opportunity to put our very best against him. Let’s just take our best shot. And we ended up on the bad side. He came through the next inning and kept us where we needed to be.”

Barlow threw 31 pitches in 1 1/3 innings but got through the ninth unscathed despite putting two runners on. That left the Royals with Payamps for the 10th, after the right-hander had made his Kansas City debut against the Astros last Thursday.

“Every one of them stings,” Matheny said. “When you have an opportunity to put it away in the last third of the game, we’ve been pretty good about figuring out how to do that. We needed some guys to throw in some spots that maybe they haven’t thrown in before. Unfortunately, [it] just got us into a spot.”

The Royals head to Seattle for the final four games of this 10-game road trip in which they’ve gone 4-2. Kansas City has won seven of its last 11 road games after losing 16 of its previous 18.

“We did enough to put ourselves in a position to win,” Merrifield said. “And it didn’t happen today. Not going to happen every time. But pretty happy with the way we’ve played, and [we need to] continue to do this and continue to figure out how to win games, which we’ve been doing a better job of lately.”