Colby Lewis was already having a disappointing May before facing Kansas City. A pair of throwing errors that led to five unearned runs for the Royals made this month a bit worse for the right-hander.
Mike Moustakas homered, Billy Butler and Brayan Pena each drove in a pair of runs and the Royals kept Texas' potent offense in check for a second straight game in a 7-4 win over the Rangers on Tuesday night.
Kansas City scored four unearned runs in the first inning after Lewis' errant throw on a comebacker to the mound sailed over the head of first baseman Mitch Moreland, putting runners on second and third with no outs.
Another error in the second led to a fifth run.
"I checked the runner (at second) and forced him back," Lewis said. "I just told myself to make a nice, easy throw and I threw it too high."
Lewis' struggles continued his May swoon — he has three losses in as many starts this month with a 6.52 ERA.
The Royals, losers of 12 straight last month, have now won five of six games.
"To come in here and win two games is big for us," said Royals manager Ned Yost. "Our pitching has been pretty good. That shows you how good."
Vin Mazzaro, making the start in place of lefty Danny Duffy, who is out for the season with a torn elbow ligament, pitched five innings and gave up three runs on seven hits. He had two strikeouts.
"It's a tough situation," Mazzaro said of the injury to Duffy. "But any situation you get thrown in you have to give it your best. You never know when you'll get another one. I just went out there and stayed focused on every pitch."
Moustakas, who reached base for a 22nd consecutive game, homered in the third.
Major league home run leader Josh Hamilton, who is only the fourth player in 40 years to lead the majors' triple crown categories 35 games into a season, according to information provided by the Rangers from the Elias Sports Bureau, extended his hitting streak to 15 games with a single and added a sacrifice fly.
Reliever Tim Collins struck out five of the six batters he faced in the sixth and seventh innings for the Royals, who swept the two-game series.
"Collins was dynamite tonight," said Yost. "The bullpen has been doing it all year long."
Lewis' throwing error on the comebacker put Eric Hosmer and Jarrod Dyson on second and third with no outs. Dyson scored on Butler's fielder's choice and Lewis retired Alex Gordon on a flyout to left field before Jeff Francoeur doubled and Moustakas was hit by a pitch. Pena followed with a two-run single to put the Royals up 3-0.
Moustakas came around to score on Chris Getz's run-scoring base hit.
Kansas City sent nine hitters to the plate in the inning.
"The only thing we can look back at is that Colby should have made that play," said Texas manager Ron Washington. "If he makes that play, it's a zero on the scoreboard.
"They swung the bat, but those at-bats wouldn't have happened if we execute some plays."
Dyson led off the second with a single and advanced to second when Lewis bounced a pickoff attempt short and wide of the bag. Butler hit a double to score Dyson and put Kansas City ahead 5-0.
The run support was plenty for Mazzaro and the bullpen, which held the majors' top-scoring team to one run in four innings. Mazzaro had made six starts with Triple-A Omaha this season, going 1-0 with a 4.37 ERA. Before his promotion May 8, Mazzaro had allowed just two runs on eight hits in 13 innings in his last two starts.
David Murphy and Mitch Moreland had RBIs for the Rangers and Brandon Snyder homered in the ninth.
Dyson reached base three times for Kansas City, including a double to lead off the game.
Notes: Rangers OF Nelson Cruz, who had home runs in consecutive games on Sunday and Monday after hitting only two in the first 34 games, sat out Tuesday. He was the only Rangers player to have played in the field in all of the team's 35 games. ... Rangers SS Elvis Andrus has hit safely in 16 of the past 19 games after failing to reach base as a pinch-hitter in the ninth and raised his average from .235 to .326. ... Moustakas is hitting .348 since Aug. 17, 2011, the third-highest mark among players with 250 plate appearances behind Detroit's Miguel Cabrera (.358) and New York's Derek Jeter (.352). ... Radio broadcaster Eric Nadel, who has called Rangers games for 34 years, will become the 15th inductee into the team's Hall of Fame on Aug. 11, officials announced. ... Among AL teams, only Kansas City's Denny Matthew currently has a longer tenure with one team than Nadel, 44 years. ... The victory marked the Royals' first two-game sweep of the Rangers since 1977.