ARLINGTON -- The Rangers have been challenging their young pitchers in some tough situations lately, but that’s the way the rest of the season figures to be as they continue to slide below the .500 mark.

Rookie reliever Emmanuel Clase was in a particularly rough spot in the eighth inning and almost escaped. That is, until All-Star shortstop Jorge Polanco ripped a two-out, three-run triple in a tie game to help the Twins complete a four-game sweep of the Rangers with a 6-3 victory on a hot Sunday afternoon at Globe Life Park.

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The Rangers now lost 10 of their last 12 games and are four games under .500.

“These are all moments that we, as a staff and players, have to learn from,” Rangers manager Chris Woodward said. “We are not just going to wipe it away and say, ‘It’s all going to be good tomorrow.’ It’s not. We need to learn from all this. Those are conversations we are all having on a daily basis.”

The game-time temperature was 95 degrees, and Rangers starter Lance Lynn struggled with his command, allowing three runs in five innings on four hits and five walks. He struck out three before leaving after 112 pitches.

“My command of the strike zone wasn’t there all day, really,” Lynn said. “When you look at their lineup, you have to be on. I wasn’t throwing enough quality strikes, and I was behind in a lot of counts and walked too many guys. I was able to stay in there as long as I could but gave them two runs early, and we were fighting the rest of the game. I have to be better from the get-go.”

The Rangers also made a couple of errors behind Lynn, and that kept him pitching in the heat longer than necessary.

“We are not going to play too many winning games if we continue to make those mistakes,” Woodward said. “Those are things we have to address and clean up. Probably cost Lynn 20-30 pitches and kept him out in the heat. Those are things we have to get better at if we are going to play winning baseball.”

Lynn fell behind 3-0 but the Rangers came back on a two-run single from catcher Jeff Mathis in the fourth and a game-tying solo homer from right fielder Shin-Soo Choo in the seventh. Reliever Taylor Guerrieri had provided the Rangers two scoreless after Lynn but had thrown 29 pitches, so Woodward turned it over to Clase in the eighth, with José Leclerc at the ready behind him.

“We thought Leclerc could go two if we needed him to,” Woodward said. “We were pretty confident with Clase. He has been throwing pretty good. He has been throwing strikes. He’s got elite stuff.”

Clase was making his seventh Major League appearance and came out throwing cut fastballs at 98-100 mph. But Ehire Adrianza led off with a single and Jason Castro doubled, putting runners at second and third.

The Rangers moved the infield in, and Clase struck out Jake Cave for the first out. C.J. Cron followed with a grounder right at shortstop Elvis Andrus, who threw home to get Adrianza for the second out. Clase then walked to Miguel Sano to load the bases and bring up Polanco.

“That young man over there has a terrific arm -- and it’s not just the velocity, which is at the absolute top of the scale at the Major League level,” Twins manager Rocco Baldelli said. “He cuts the ball and gives you a really challenging, unique look. Usually left-handers have a very difficult time against him. Those are not easy at-bats, none of them.”

Clase missed with two cut fastballs and then threw one for a strike. He threw a fourth straight cutter, and Polanco lined it into the gap in right-center field for the go-ahead triple. Clase’s pitch was clocked at 99 mph, and Polanco’s exit velocity was 102.7.

“It wasn’t a terrible pitch, down and in,” Mathis said. “When a guy is throwing 100 mph with cut, you just want to get it in the zone and hope the guy hits it on the ground. Polanco just did a good job.”