OAKLAND — The Royals were denied a chance to take the lead in the top of the eighth and they lost the game in the bottom of the inning, when Matt Chapman blasted a solo homer to left off reliever Jason Adam for the winning run in a 3-2 loss to the A’s at the Coliseum on Sunday.

The Royals dropped three out of four in Oakland and have lost eight of their last 10 games. This loss came at the hands of a run-saving defensive play by A’s shortstop Marcus Semien, who threw out Whit Merrifield trying to score the go-ahead run from third with one out in the eighth on a hard-hit ground ball by Salvador Perez. Semien dived to corral the ball and fired from his knees to catcher Jonathan Lucroy, who tagged out Merrifield.

Manager Ned Yost said that Merrifield could’ve gotten a better jump from third, but that he was going on contact.

“It’s a gamble play where you’re just selling out and going,” Yost said. “Just made a nice play.”

In the ninth, Alex Gordon doubled off A’s closer Blake Treinen, but was stranded at third after Drew Butera fouled out to Lucroy to end the game.

Brad Keller pitched his longest outing of the season and left with a no-decision after 5 1/3 innings, allowing two runs on five hits with four walks and a career-high four strikeouts. Yost said before the game that Keller would be stretched out to 90 pitches; Keller departed after 85 in his third start of the season.

“I was hoping we could score a run or two for him and give him a win, but [he] did a good job of holding the fort,” Yost said.

Keller’s only blemish was the second inning, when he allowed two runs after walking Chapman and giving up a double to Mark Canha to put runners on second and third with nobody out. Stephen Piscotty knocked in a run with a slowly hit ground ball and Lucroy singled up the middle to give the A’s a 2-0 lead. Keller said he calmed down after giving up the double to Canha, escaping a bases-loaded jam later in the inning by striking out Khris Davis.

“Got a ground ball to third base, just slow,” Keller said. “And then a chopper over my head, made a good pitch, but just found a hole. Walked a guy, but right after that, came out there and settled down. I just attacked Khris Davis with fastballs.”

The Royals answered with two runs in the third off A’s starter Sean Manaea, thanks to some help from the sun. Merrifield led off the inning with a fly ball that fell in front of Canha, who lost track of the ball in left field. Merrifield eventually scored on a wild pitch by Manaea, and then Perez launched a solo homer to left to tie the game at 2-2.

Keller and Royals’ bullpen pitched in and out of trouble all day. Royals pitchers stranded eight runners, including bases-loaded jams in the second and sixth innings and a runner at third with nobody out in the seventh.

Keller said he got into a groove after the second inning, and escaping trouble helped his confidence.

“I felt more of a groove. Especially right after the second inning, I was starting to get the hang of things,” Keller said. “To be able to bear down and make pitches when you need to, that will always give you confidence.”

But the Royals had no defense for Chapman, who drilled a 93 mph fastball from Adam just above the yellow line on the out-of-town scoreboard in left field.