Kansas City, Mo. ? Bobby Crosby’s biggest defensive gaffe of the season led to his best day at the plate.

Never mind that eight days separated Oakland’s 3-2 loss to Minnesota on May 8 — when Crosby dropped a fly ball and allowed the winning run to score from first in the 10th inning — and his first career three-hit game in Sunday’s 6-2 win over the Kansas City Royals.

To Crosby, who homered and drove in two runs, one had everything to do with the other.

“That incident kind of cleared my mind,” he said. “I just decided to get up there and swing and stop thinking and worrying about whether I’m doing this or that. Ever since then, I’ve felt great at the plate.”

Crosby had a solo homer in the fifth inning and an RBI single in Oakland’s three-run seventh. He doubled and scored in the ninth.

Erubiel Durazo also homered for the A’s, who won their seventh straight against the Royals — all in Kansas City — and have won seven of their last 10.

Oakland left-hander Barry Zito (3-3) gave up Joe Randa’s two-run triple in the first inning, but recovered to pitch through the sixth before giving way to Jim Mecir.

Mecir, Chad Bradford and Arthur Rhodes closed out the game with one shutout inning each. The bullpen did not allow a run in 14 innings during the Athletics’ six-game road trip.

“The bullpen’s been great,” Zito said. “They’ve done what we know they can do.”

Zito gave up two runs on four hits, striking out three. He walked two and hit two batters in earning his first decision since a 7-5 loss to the New York Yankees on April 29 — three starts.

Brian Anderson (1-5) lost his fifth straight start for the first time since Aug.-Sept. 1995. He lasted 6 1-3 innings, giving up four runs on seven hits with two strikeouts and no walks.

After Zito hit Desi Relaford with a pitch to open the game and walked Ken Harvey with two outs, Randa’s fly ball — kept in play by a stiff southeast breeze — fell just out of Jermaine Dye’s reach along the right-field line. It rolled to the wall in foul territory, then bounced back past Dye into the outfield as the bases cleared.

“That was just a weird play,” Zito said. “That ball’s in the stands nine times out of 10.”

Crosby’s fifth-inning homer made it 2-1, and the A’s tied it at 2 with back-to-back doubles by Durazo and Damian Miller.

The homer barely cleared the glove of leaping center fielder Carlos Beltran and bounced back onto the field after going over the wall.

“I knew it cleared,” Crosby said. “I was watching it intently.”

In the seventh, Crosby’s bloop single over shortstop Angel Berroa chased Anderson and put Oakland up 3-2. Mark McLemore — playing for the first time since being activated from the disabled list on Tuesday — followed with an RBI double off Jason Grimsley for a 4-2 lead.

“You think this is going to be the day, and it turns out to be as rotten as — maybe worse than — the rest,” Anderson said. “You look at the other (losses), and they were no-doubters.”

Durazo led off the ninth with a homer off Shawn Camp for a 5-2 lead, and Mark Kotsay’s sacrifice fly off Jaime Cerda made it 6-2.

Randa doubled in the sixth inning, giving him two of Kansas City’s five hits. The Royals have now gone nine straight games without double digits in the hit column.

“It’s frustrating,” Randa said. “The pitchers have stepped it up and done their job, and we’re not carrying our end.”

Notes: Kelly Stinnett, the Royals’ backup catcher, has appeared in only 10 games this year but has hit safely in all 10. He extended the streak with a fourth-inning single. … Oakland has homered in 17 of its last 18 games and 26 of the last 28. … The Athletics have played 20 series in which they started Tim Hudson, Mark Mulder and Zito. This is the sixth series sweep by that rotation and the first since Aug. 28-30 at Baltimore. … Kansas City executive Herk Robinson retired Sunday, ending a 35-year stay in the Royals’ front office that included 10 years as general manager. Robinson, 63, has been the team’s chief operating officer for the last four years.