ARLINGTON — The Royals found themselves on the wrong end of a pitching duel in Sunday’s 5-1 loss to the Rangers, striking out 11 times against Texas starter Adrian Sampson and wasting a solid effort by Kansas City starter Brad Keller.

The Royals struck out 47 times in the four-game series in Arlington, losing the last three of those contests. They walked only seven times in the series and scored only nine runs total in their farewell trip to Globe Life Park.

“When you miss mistakes, these guys are good up here, so it’s going to be tough to hit their pitches,” said Royals leadoff hitter Whit Merrifield, who struck out twice on Sunday. “It seems like all series, we didn’t do a good job of hitting balls that split the plate, and when that happens, you’re forced to try to battle against good strike-to-ball sliders or fastballs on the corners, and that results in a bunch of strikeouts.”

Kansas City squandered a bases-loaded, no-out chance in the fifth inning. They started the frame with three consecutive singles, including two bunt hits.

“I was a little unhappy about it,” Sampson said. “I have my feelings about bunting, but you’ve just got to … it’s part of baseball. You’ve just got to deal with it and just keep making your pitches.”

Indeed, Sampson dealt with it. Merrifield lined out to third base for the first out, and then Sampson struck out the next two hitters.

“He made an adjustment,” Royals manager Ned Yost said. “I think from the time we got the bases loaded, he threw two fastballs. He just went soft — changeups and slow curveballs. He just did a good job. A lot of times a young pitcher will get in that situation and want to try to power his way through it. He did just the opposite. He totally abandoned his fastball and went soft.”

Keller, for his part, certainly pitched effectively enough Sunday to give the Royals a chance to win had their hitters figured out how to handle Sampson. Keller pitched seven innings, tied for the most he’s thrown in any start this season, and yielded three earned runs on nine hits while striking out six.

He threw 100 pitches, including the most strikes he has ever thrown in 33 career Major League starts.

“I thought Keller was fantastic,” Yost said. “His strike-to-ball ratio was off the charts, 75 strikes to 25 balls. He was on the attack … I thought he threw the ball excellent. I was very, very pleased with his outing.”

Perhaps most impressively, Keller did not walk a batter. He entered the day leading the Majors with 42 walks, but only issued one free pass in his last start.

“I was able to go out there and pound the strike zone, something I haven’t been doing in previous starts, so to go out there and do that today was definitely a step in the right direction,” Keller said. “When you give up hits that just kind of fall into place, or ground balls that find holes, that’s frustrating. But as long as I’m inducing weak contact and going after guys, it’s definitely encouraging.”

The Rangers scored the game’s first run in the second when Hunter Pence scored on Ronald Guzman’s ground-ball single to left.

Texas scored twice off Keller in the fifth inning, once on a wild pitch and the other on an RBI single by Nomar Mazara. Those runs were all the support Sampson needed as he continued to rack up K’s. Sampson scattered eight hits, including the Royals’ lone run on Jorge Soler’s sixth-inning homer.

After Sampson left, the Royals threatened in the eighth against relievers Shawn Springs and Shelby Miller. They loaded the bases again before Cam Gallagher lined out to center to end the inning. The Rangers scored twice in the eighth to put the game away.