KANSAS CITY — As the crowd thundered its approval, David DeJesus endured a violent and lengthy congratulation from his teammates at Kauffman Stadium last week.

It was hard to blame the mob assembled at home plate for its enthusiasm. After all, it had been waiting awhile for such an opportunity.

With his last-gasp blast in the ninth inning, the Royals’ veteran outfielder ended the team’s three-year drought without a walk-off home run — the first since April of 2005. His 10th long ball of the year assured them a fourth-place spot going into the All-Star break.

Semantics? Maybe. But lost in the Royals’ slow climb out of the cellar and back into respectability was one of the club’s better power exhibitions in the past decade.

“From time to time, we get hot and we get cold, but the offense is coming around pretty good,” said Jose Guillen, who was right at the center of the swarm. “The talent is here.”

In the brittle, 100-loss seasons of the David Glass era, Kansas City’s offense has often been mostly that — offensive.

Perpetually mired among baseball’s least-scoring teams, the Royals have been outscored in every full season since 1991. Those deficits in run differential became even greater in recent years when the team slipped from proud franchise to league doormat.

After a strong start to the season, early swigs of optimism were soon drowned by another double-digit losing streak — 12 in a row, that eventually lasted half of May. Dominant pitching performances went to waste and left the entire clubhouse searching for answers.

“It’s frustrating, but anytime you’ve got a young team, you’re going to go through those struggles.” Royals hitting coach Mike Barnett said. “When you go through a bad stretch like that, you kind of press a little bit.”

On the final day of May, the team bid adieu to its losing streak and its power outage.

Light-hitting infielder Mark Gruzielanek opened June with his first homer. Outfielder Mark Teahen seemed to rediscover his power stroke and homered in three straight games. Then Jose Guillen fanned a spark into a blaze by pounding six extra base hits four of them out of the yard during a four-game stint in New York.

By month’s end, the team without a dominant slugger knocked out 30 home runs for the first time since 2004 when Carlos Beltran and Mike Sweeney provided a potent 1-2 power punch that hasn’t been seen since.

“We’ve been a young club for a long time, and the only difference between younger and older players is consistency, more or less,” Teahen said. “It’s a sign that some of our young players are starting to be a little more mature and turn into the ball players they were projected to be.”

He might as well include himself in that assessment.

Teahen, DeJesus and third baseman Alex Gordon all have double-digit home runs totals already and have flashed the power scouts hoped they’d live up to. Filled with young and unproven talent three years ago, the core of the team which also includes catcher John Buck is entering its prime simultaneously.

From Barnett’s standpoint, the power boost is simply one by-product of his players’ increased maturity and consistency at the plate.

“It’s a matter of constantly making adjustments, being aware of what’s going on and trying to adjust a little quicker,” Barnett said. “That’s something that comes with experience and time.”

A couple new faces also provided some more pop in the lineup.

Guillen, a polarizing free-agent signing, has lived up to his billing as a dynamic slugging threat with a team-leading 13 homers and 65 RBIs — fourth-best in the American League.

More surprisingly, shortstop Mike Aviles made the leap from the minor league without much of a learning curve. The 27-year old rookie replaced anemic-hitting Tony Pena, Jr. in the lineup and started mashing from the get-go. After just a month and a half, he leads the team in batting average and slugging percentage.

“Hitting is very contagious,” Aviles said. “When a couple guys start getting on base and getting pumped up, everybody else says, ‘I’m not going to be the next guy to make an out. Let’s keep this thing going.’”

Despite the mild resurgence, Kansas City’s offense still has a few glaring holes to patch, a serious lack in walks among them. The Royals rank last in baseball with 223 bases on balls, a number that Barnett believes will improve along with a solid approach in the batter’s box.

“You’ve got to start having some success as an offensive player to get to where clubs respect you at the plate,” Barnett said. “It’s easy to talk about, but you’re not going to do it by going up there and just taking pitches.”

It’s no secret that club officials, general manager Dayton Moore chief among them, have put a significant priority on pitching and defense in the past two years. Such focus has produced perhaps the most stable rotation in years and a bullpen that tends to avert disaster.

But don’t expect the power boon to continue, at least not at such a steady clip.

Instead, the Royals’ offense will have to rely on Kauffman’s yawning gaps (the team ranks 12th in doubles) and consistent, timely production from all parts of the lineup to help keep them out of the cellar and headed in the right direction.

“We don’t have anybody that’s going to go out and hit 40 homers, so we have to be consistent through the lineup and have everybody contribute at little bit,” Teahen said.

“It’s nice that we’re getting that production up and down the lineup. Hopefully, it continues.”

Sports reporter Andy Meyer can be reached at andymeyer@npgco.com