ARLINGTON, Texas -- Back-to-back walks left Minnesota's Francisco Liriano with an unsightly six free passes and Ron Gardenhire with a decision to make in the seventh inning.
The Twins manager stuck with his teetering left-hander for one more batter, and Liriano responded with a strikeout that helped quell the final threat from a struggling Texas offense in Minnesota's 5-1 victory on Friday night.
The loss was a season-high fifth straight for the AL West-leading Rangers. Star outfielder Josh Hamilton left early with back spasms and was listed as day to day.
"We just wanted Liriano to get through it," Gardenhire said. "Those are big moments for him. We trust him. We don't want to extend our bullpen too much, and he got a big out there."
First baseman Mike Napoli misplayed Josh Willingham's two-out popup for a two-base error that cost the Rangers two runs while the Twins were building a 4-0 lead, but a potentially bigger error didn't affect the scoreboard.
Hamilton, the leading vote-getter for Tuesday's All-Star game, exited soon after misplaying Brian Dozier's fly ball to left field for a three-base error and making a long throw from the warning track in the fifth inning. Hamilton said he first felt a twinge as he broke on the ball.
"I've iced it three times already. It feels a little better than it did," he said. "It kind of scared me when it first happened because I didn't know what to expect from a spasm like that. I had some weakness in my legs."
Mauer drove in his two runs on a single that scored the only earned run in a three-run third and a sacrifice fly in the fourth. Morneau had an RBI single in the third and hit his 11th home run on a line drive into the right-field seats off Tanner Scheppers in the seventh.
The best chance for Texas came in the sixth when Adrian Beltre singled, Michael Young walked and Nelson Cruz hit an RBI single. With no outs, Napoli deepened his slump by hitting into a double play, and the threat ended with one of three strikeouts by Yorvit Torrealba.
"I've been through that before," said Napoli, hitless in his past 21 at-bats with runners in scoring position. "It's part of the game. I'm just going to keep going."
The absence of Hamilton showed in the seventh when Liriano walked Ian Kinsler and Elvis Andrus back-to-back, bringing up Hamilton's replacement, rookie Leonys Martin. Gardenhire stuck with Liriano even after Rangers manager Ron Washington went to pinch-hitter Brandon Snyder. After Liriano struck out Snyder, reliever Jared Burton got Beltre on a flyout.
"I've been walking too many guys late in the game, but they have some good hitters, and I made some mistakes with those guys," Liriano said. "So I was just trying to keep my ball down, just try to get them out. If they don't swing, then just go on to the next batter and make my pitches."
The Rangers still have the best offense in baseball -- statistically -- but they've hit their second significant lull in the last month. Texas has scored two runs or fewer in four of the past five games after a similar drought in early June.
"We hit a funk," Washington said. "And the only way we can come out of it we have to keep grinding and play our way through it."
The Twins sent up eight batters in the third, but only because Napoli couldn't handle Willingham's easy two-out popup that landed untouched just inside the foul line behind first base. Mauer scored on the two-base error, and Morneau added another unearned run with a single that scored Willingham.
Rangers rookie left-hander Martin Perez (1-1) was solid in his second career start, allowing six hits and four runs -- two earned -- in six innings with three walks and three strikeouts.
"He certainly showed some heart," Washington said. "The pitches piled up after we didn't catch that popup, and I didn't think he would get into the fifth inning."
This week's sweep by the Chicago White Sox was the first three-game sweep of the Rangers since June 14-16 last year against the Yankees. Texas had a major league-best streak of 52 straight series of three games or more without getting swept. ... Friday night's crowd of 47,240 was the Rangers' fourth straight sellout. It's the third time this year they've had a sellout streak of at least four games, the franchise record going into the season. ... The Twins had 15 hits in their 7-3 loss to the Tigers on Thursday. It was the first time they had that many hits in a loss since Sept. 25, 2010, also at Detroit. ... Sam Deduno will make his first major league start for the Twins on Saturday. He has 5 2/3 innings of big league experience with San Diego and Colorado. He will be the Twins' 11th starter, most in the majors.