KANSAS CITY, Mo. -- The White House one day, the sweat house the next.

Danny Duffy threw 6 2/3 solid innings and Cheslor Cuthbert homered as the Kansas City Royals bested the struggling Texas Rangers 3-1 on Friday night with 98 degrees and a stifling heat index of 108 for the first pitch.

The Rangers, who had the best American League record (51-27) and a 10-game lead in the American West on June 28, have lost 15 of 19 since and their lead has shrunk to 2 1/2 games over the Houston Astros.

The Royals, who visited the White House on Thursday to be honored by President Barack Obama for winning the 2015 World Series, won for only the sixth time in 17 July games to move one game above .500.

"I think being around the guys on an off day was a positive," Duffy said. "We got to do something not a lot of people get to do."

Duffy (6-1), who did not move into the rotation until May 15, yielded one run on four hits over 6 2/3 innings. He is 5-0 in his past eight starts and has pitched at least into the seventh inning in his last five turns. Because of Duffy's inconsistency, he began the season in the bullpen but has become the Royals most reliable starter.

"You have a basic idea of what you're going to get now," Royals manager Ned Yost said. "Where before, you knew he had great stuff, but you weren't quite sure what you were going to get."

Duffy was pulled in the seventh after walking Ryan Rua and giving up a two-out single to Nomar Mazara. Luke Hochevar was summoned to face pinch hitter Mitch Moreland, who lined out to a retreating Paulo Orlando on the right-field warning track after a 10-pitch at-bat.

"The ball that Mitch hit there late as a pinch hitter, he hit it about as good as you can hit it," Rangers manager Jeff Banister said. "It was a nice running catch in right field. If they don't make that play there, it's a different story and probably a different outcome. I felt like we had some good at-bats. We just couldn't string them together."

Yu Darvish (2-2) gave up three runs (two earned) and seven hits while striking out 11 and walking one in six innings, throwing a season-high 91 pitches. Darvish is 0-2 in two starts since coming off the disabled list July 16.

"For Yu to come back with 11 strikeouts and one walk, three of which were after a leadoff triple, for him to come back in his second start and have those type of pitches and bear down like that and really make some great pitches to come off the field without giving up anything, shows me his competitive edge," Banister said. "It also showed me the life of the pitches are there. Look for big things the next few starts from Darvish. I feel really good about where Yu is at and what he showed us tonight."

After Kelvin Herrera worked a 1-2-3 eighth inning, Wade Davis closed it out, logging his 21st save in 23 chances.

The Royals scored an unearned run in the first inning when Alcides Escobar led off with a single, stole second and motored to third on catcher Bobby Wilson's throwing error. Escobar scored on Eric Hosmer's groundout to first baseman Ryan Rua.

Kansas City added a run in the second, which began with Darvish walking Alex Gordon. He swiped second, stopped at third on Paulo Orlando's single and scored on rookie Whit Merrfield's ground single to center.

The Rangers loaded the bases in the third on an Elvis Andrus walk, a Delino DeShields single and Jurickson Profar hit by a pitch but came away with nothing. Danny Duffy struck out Ian Desmond on three pitches to end the threat.

Rookie Cheslor Cuthbert homered on a 3-1 Darvish fastball to lead off the Royals' third. Cuthbert extended his career-high hitting streak to 11 games. He has driven in a run in 12 of his past 15 home games.

Rougned Odor homered in the fourth for the Rangers. He became the first left-hander to homer off Duffy during the regular season since Jim Thome on Aug. 27, 2011, a span of 358 at-bats. Odor, who has a career-high 18 home runs, has hit 11 since June 6.

Gordon led off the Royals' fourth with his first triple of the season but went no farther after Darvish struck out the next three batters -- Orlando, Merrifield and Jarrod Dyson.

Darvish struck out 10 in the first five innings, his 27th career double-figure strikeout game but his first since July 18, 2014. Only Nolan Ryan with 34 has more in Rangers history.

"I was able to go six and walked only one guy," Darvish said through an interpreter. "I felt like I had a good fastball and that made my slider better."

NOTES: The Rangers activated rookie LHP Jake Diekman from the 15-day disabled list and he pitched a scoreless seventh. Diekman had not pitched since July 5 because of lacerated left index finger. LHP Cesar Ramos, who was 3-3 with a 6.04 ERA in 16 games, including four starts, was designated for assignment. ... Royals CF Lorenzo Cain, who is on the disabled list with a strained left hamstring, participated in pregame drills. "We're making progress," Royals manager Ned Yost said. If Cain has no setbacks, he could begin a minor league rehab assignment Monday. ... It was University of Missouri night at Kauffman Stadium with Barry Odom, who has replaced Gary Pinkel as football coach, making the ceremonial first pitch. ... Rangers manager Jeff Banister said RHP Kyle Loshe is still penciled in for a Monday start against Oakland. Loshe is 0-2 with a 12.54 ERA in two starts. Banister acknowledged RHPs Martin Perez and Nick Martinez are possibilities. ... Rangers LHP Cole Hamels and Royals RHP Yordano Ventura are the Saturday probables.