Kansas City, Mo. ? The revamped Oakland Athletics are built for speed, not power. Get on, run the bases aggressively, score whenever and however you can.

This recent power surge? Not even they can explain it.

Bobby Crosby homered twice and Ryan Sweeney hit a three-run shot, lifting the Oakland A’s to a 6-3 victory over the Kansas City Royals on Sunday.

The AL’s worst home run-hitting team got long balls early and late on a hot, humid day, winning consecutive series for the first time since June 2-8 against the White Sox and Orioles.

“Home runs seem to come in bunches,” Crosby said after his first multihomer game in five years, second career. “I know personally they do and team-wise they do. I don’t really know the reason for it. Guys swings are going well and that’s usually when it happens.”

Sweeney and Crosby hit consecutive homers in the second inning off Luke Hochevar (6-5) to stake Brett Anderson to an early 4-0 lead. After the Royals scored three runs in the seventh to get within one, Kurt Suzuki hit a solo homer in the eighth and Crosby had one in the ninth to put the A’s up, 6-3.

That’s four homers in a game twice in five days, bumping Oakland (93) past the Royals (92) at the bottom of the AL homers list.

“The weather’s warm, the balls carrying pretty good, we’ve got some guys working hard, and it’s starting to show,” A’s manager Bob Geren said.

Defense kept it close early.

Royals shortstop Yuniesky Betancourt made three superb plays, including a back-to-the-infield grab of Tommy Everidge’s blooper in short left in the fourth inning. Alberto Callaspo, making a spot start at third base, also made a sprawling stop on Suzuki’s shot down the line in the sixth inning.

Sweeney had Oakland’s best defensive play, following his homer in the second inning with a diving catch in right on Betancourt’s slicing liner in the bottom half, saving extra bases.

“Everybody played good defense out there today,” Hochevar said.

Anderson (7-8) didn’t need much help early, scattering five hits over the first six innings.

The heat started to wear down Anderson in the seventh and when the Royals opened with three straight hits against the rookie left-hander, chasing him on Bryan Pena’s run-scoring single. Kansas City scored twice more on fielder’s choices by Mitch Maier and Josh Anderson, pulling within 4-3.

That was as close as Kansas City would get.

Suzuki made it 5-3 with a solo homer off Roman Colon and Crosby led off the ninth with his sixth homer off John Bale, making Anderson a winner after allowing three runs on six hits in six innings.

Andrew Bailey pitched a perfect ninth for his 11th straight save, 16th in 20 chances overall.

“It’s tough going place to place and you have to get used to one for three or four games, then you go to Oakland where it’s cool,” said Anderson, still battling an undiagnosed finger injury. “It’s a little bit of a shock and I kind of wore down in the seventh, but up until that point I felt good.”

Hochevar struggled early, got better late.

The right-hander walked the leadoff hitter in the first two innings, escaping trouble in the first on Betancourt’s dive-and-flip-with-his-glove forceout at second. Betancourt made another nifty play in the second inning, leaping to snare Everidge’s rising liner with runners on second and third.

“He showed his athleticism,” Royals manager Trey Hillman said. “We like the way he moves his feet. We like his hands, his exchange and his arm from Day 1.”

Betancourt couldn’t do anything about the next three pitches: Sweeney hit an 0-1 offering out to right for a three-run homer to right, Crosby sent the next one out to left to put the A’s up 4-0.

Hochevar opened the fourth inning by hitting Rajai Davis with a curveball, letting out a scream in frustration. He settled down after that, though, allowing four hits over the next five innings.

Hochevar allowed four runs in seven innings overall after giving up 11 runs over the previous 11 innings.

“Two mistakes I paid for,” said Hochevar, 0-3 career against Oakland. “Both of them were unexecuted pitches. That especially can’t happen with runners in scoring position.”

NOTES: The game included seven stolen bases — four by Oakland — and two pickoffs, both by Hochevar. … The A’s became the first team in 12 years to start rookie pitchers in nine straight games. They won seven of those. … Kansas City faced a left-hander for the fifth time in seven games. … Crosby’s only other two-homer game was May 21, 2004, at home against Kansas City.