OAKLAND, CALIF. ? Before taking the mound in the eighth inning, Mark Mulder told catcher Damian Miller he had to throw six pitches to stay under 100 and guarantee himself a shot at finishing the game.

Mulder got out of the inning in five.

He carried a no-hitter into the seventh and pitched his third straight complete game, and Bobby Crosby backed him with a pair of homers Friday night in the Oakland Athletics’ 7-0 victory over the Kansas City Royals.

Mulder pitched a three-hitter for his eighth career shutout, his first since blanking the Chicago White Sox on May 6 last year.

Mulder has thrown three straight complete games for the third time in his career.

“I like throwing complete games,” he said. “I want to finish what I started.”

Mike Sweeney singled through the hole at shortstop leading off the seventh for Kansas City’s first hit, and Wilton Guerrero followed with another single. Joe Randa then hit into a double play, and Ken Harvey struck out.

At 13-26, the Royals are off to the worst start in club history after 39 games.

Mulder worked in his typical quick fashion, making only 20 pitches through the first two innings. He retired the first seven batters and 15 out of 17 to start the game, hitting Kelly Stinnett with a pitch in the third and then plunking reigning AL Rookie of the Year Angel Berroa two batters later. Mulder retired the next seven before hitting Mendy Lopez with a pitch leading off the sixth.

“Obviously, I feel strong going into each start,” Mulder said.

6Sports video: Royals defeated, 7-0

The left-hander struck out six and walked none, improving to 8-0 with a 1.72 earned-run average in nine starts against Kansas City. He finished with 108 pitches.

“There’s no question he was unbelievable today,” said Royals manager Tony Pena, whose team lost, 3-1, to Mulder last weekend. “Not only did he have really good movement on his fastball, but he also has a great slider, making it tough for hitters.”

Oakland has won three straight and nine of its last 11 to move a season-high five games over .500.

The A’s beat the Royals for the eighth straight time, their longest streak against Kansas City. Oakland swept the Royals in Kansas City last weekend and looked good against them again, pounding 12 hits and jumping out to an early lead.

Crosby and Marco Scutaro homered in back-to-back at-bats in the third.

Crosby connected for a two-run homer — the sixth of the season for the rookie shortstop — on a 1-0 pitch from Brian Anderson (1-6) with two outs, sending the ball into the left-field seats. Scutaro followed with his first homer of the year, a solo shot to center on full count.

Crosby homered again in the fifth, also to left, for his seventh homer that gave him his first career multihomer game. They were his first two home runs in Oakland this year.