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. Gray 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. 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. The A's struggled to get anything going and lost for the third time in four games a day after trading two-time reigning Home Run Derby champion Cespedes to the Red Sox for Lester and Jonny Gomes. Greg Holland followed scoreless innings by Kelvin Herrera and Wade Davis for his 30th save in 32 chances — and third in as many games. 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 Saturday. Center fielder Coco Crisp received pain-relieving trigger-point injections in his strained neck over recent days but missed his fifth straight game.