Adrian Beltre’s three-run homer in the first inning Wednesday night started the Royals on a frustrating treadmill of endless catch-up – and they never quite got there in a 7-6 loss to the Texas Rangers at Kauffman Stadium.

Beltre’s no-doubt boomer against spot starter Everett Teaford definitely set the tone.

“He’s swinging the bat well,” Teaford said, “and I just left a breaking ball up. When you do that to a good hitter, stuff like that can happen.”

Cue the see-saw.

The Royals scored single runs in the first and sixth innings against Texas starter Ryan Dempster before the Rangers spanked relievers Vin Mazzaro and Aaron Crow for three runs in the seventh.

Michael Young ignited that burst with a leadoff homer against Mazzaro.

“We played catch-up all night,” manager Ned Yost said. “We’d get close, and they’d tack on. We just really couldn’t do much with Dempster. He really located his pitches extremely well. He worked on the knees on both corners.”

Back came the Royals with two runs in their seventh against Alexi Ogando before the Rangers answered with one in the eighth against Jeremy Jeffress. Then the Royals got one back in their eighth against Mike Adams.

Get the idea?

Billy Butler had three doubles in fueling nearly everything the Royals did offensively. He had an RBI double in the first. His two-out double in the sixth preceded Salvy Perez’s RBI double in the sixth.

Butler’s third double came with one out in the eighth and led to the Royals’ fifth run.

Texas closer Joe Nathan, a longtime Royals nemesis with the Twins, permitted one run in the ninth – but only one – before securing his 29th save in 30 chances.

Not quite enough.

“You don’t want to fall behind a team like that,” third baseman Mike Moustakas said. “They’re such a good offensive team, and Dempster threw the heck out of the ball tonight. Everything was down.”

Dempster improved to 5-1 since arriving July 31 from the Cubs just prior to the non-waiver trade deadline. He limited the Royals to four hits in six innings before handing a 6-2 lead to Ogando.

Say this: The Royals made it interesting. First, they slapped Ogando for two runs in the seventh. Jeff Francoeur drew a leadoff walk and went to third on Eric Hosmer’s sharp single through first baseman Mitch Moreland.

Ogando then threw a wild pitch that scored Francoeur and moved Hosmer to second. Hosmer came around on successive fly balls to right by Johnny Giavotella and David Lough. That closed the gap to 6-4.

But back came Texas.

Beltre started the eighth against Jeffress with a lightning bolt to left that caromed off the wall past Alex Gordon’s desperate leap for a triple. Nelson Cruz followed with an RBI single to center.

Butler got his third double on a one-out drive into short left-center in the eighth. Center fielder Josh Hamilton tried for a diving catch and came up short. A wild pitch and an infield grounder produced the run.

Teaford, 1-4, recovered from Beltre’s three-run homer to work into the fifth before exiting after a one-out walk. He threw 72 pitches on three days of rest after working 5 1/3 innings Saturday in the second game of a double-header.

“Dempster is a good pitcher,” Teaford said. “So runs are going to be tough to come by off him. Then to give them a three-run cushion out of the gate obviously is not acceptable.”

Mazzaro replaced Teaford and worked through the sixth with no problems before getting roughed up in the seventh.

“The seventh inning did us in,” Yost said. “The three-run seventh. Even if we could have just kept it to two, we’d have been in better shape. Their tack-on runs doomed us.”

Beltre’s homer in the first followed a leadoff single by Ian Kinsler through the left side and a one-out walk to Hamilton. Beltre then crushed a drive to left for his 29th homer of the season.

“He’s as hot as anybody in the league,” Yost said. “Anything up, he’s smashing it. If you’re going to get him out, you’ve got to do it down. You’ve got to change speeds, execute pitches and work the corners.

“You can’t throw anything down the middle because he’s going to hit it a long way.”

The Royals got one run back in their first on Butler’s two-out RBI double off the top of the wall in right-center field. That close to his 100th career homer.

Dempster didn’t allow another hit until Hosmer’s one-out single in the fifth. But Giavotella struck out, and Lough grounded out to third.

The Royals closed to 3-2 in the sixth on two-out doubles by Butler and Perez, who extended his hitting streak to 10 games. Dempster prevented further damage by retiring Moustakas on a fly to center.

That seemed to rouse the Rangers.

Mazzaro gave that run right back by coughing up a leadoff homer to Young in the seventh. It was Young’s second homer of the series; he had just four prior to Monday’s opener.

Geovany Soto drew a one-out walk and went to third on Moreland’s pinch double. That prompted the Royals to bring in Crow and shorten their infield.

It didn’t work.

Kinsler sent a drive to deep left, which resulted in a sacrifice fly when Gordon made a circus catch at the wall. Elvis Andrus followed with a floater into short left-center for an RBI single that made it 6-2.