Oakland, Calif. ? Raul Ibanez homered to break his own franchise record for oldest Royals player to clear the fences, and Kansas City beat the Oakland Athletics 1-0 on Friday night.

The 42-year-old Ibanez connected in the fifth inning for his fifth homer, giving Jeremy Guthrie the lone run he needed for Kansas City’s first victory at the Oakland Coliseum since April 10, 2012. The Royals went 1-5 against the A’s last season, including 0-3 on the road.

Guthrie (7-9) struck out six in six innings to win his second straight outing following a three-start skid as the Royals beat the team with baseball’s best record for their third straight win and eighth in 10. It could get tougher today, when Jon Lester makes his A’s debut two days after being traded by the Boston Red Sox.

The A’s struggled to get anything going and lost for the third time in four games a day after trading slugging left fielder Yoenis Cespedes to the Red Sox for Lester and Jonny Gomes.

Sam Fuld started in center field and batted leadoff one day after returning to Oakland where he began the season following a trade from Minnesota. His leadoff double in the fourth was the first hit off fellow ex-Stanford player Guthrie.

Guthrie struck out the side in the sixth, retiring Brandon Moss and Jed Lowrie on consecutive called third strikes.

Sonny Gray (12-4) hung tough in a pitcher’s duel with Guthrie. The right-hander struck out seven in seven innings and didn’t walk a batter for the first time all year.

He had his five-start winning streak snapped with his first losing decision in eight outings dating to a June 13 home loss against the Yankees.

He had five or more strikeouts in each of his five July outings, going 5-0 with a 1.03 ERA.

Nori Aoki doubled leading off the game and advanced on a wild pitch, but Gray retired the next three batters in order to avoid damage.

Greg Holland followed scoreless innings by Kelvin Herrera and Wade Davis for his 30th save in 32 chances.

Trainer’s room

Royals first baseman Eric Hosmer, who will be out three to six weeks after sustaining a stress fracture of the third finger on his right hand Thursday, is likely headed to the disabled list today. Manager Ned Yost said more testing is likely but a hand specialist has already evaluated him.

“It’s a non-displaced stress fracture,” Yost said. “That means it doesn’t need to be casted, doesn’t need surgery, just needs time to heal. He’s a pretty quick healer, but it’s probably going to be a 3-4 week ordeal.”