Wilson Betemit hit his first career grand slam and Bruce Chen picked up his 10th victory as the Kansas City Royals beat the Oakland Athletics 6-3 on Wednesday night.
Betemit, who homered and drove in four runs Tuesday, worked a full count from Trevor Cahill and fouled off the next three pitches before homering just inside the right-field pole in the third inning.
Mitch Maier doubled, Jarrod Dyson had an infield single and Billy Butler walked before Betemit's 12th home run that snapped Cahill's 15-inning scoreless streak.
Chen (10-7), who was 1-13 from 2007-09, gave up three runs in the first two innings. He went five innings, allowing three runs, six hits and a walk. Chen, who started the year in the minors, leads the Royals in victories.
Mark Ellis and Kurt Suzuki had run-scoring singles in the A's first. Matt Carson homered in the second on the first pitch from Chen, giving the A's a 3-0 lead.
Joakim Soria worked the ninth for his 38th save in 40 opportunities and he has converted 31 consecutive saves.
Cahill (16-7), who was 7-2 with a 1.69 ERA in his previous nine starts, allowed six runs, six hits and three walks in five innings.
While Cahill has limited right-handed hitters to a .184 batting average, the lowest in the majors, he has yielded 11 home runs to right-handed batters. Butler, one of three right-handed hitters in the Kansas City lineup, homered in the fifth with Mike Aviles aboard.
The second-place A's dropped 10 games behind the Texas Rangers, who beat Detroit 11-7, in the AL West. They are a game below .500 (72-73).
Chris Carter went 0 for 4 and is hitless in 24 at-bats to begin his major league career. The A's record to start a career is 0 for 25 by Bill McNulty in 1972.
Notes: Royals 1B coach Rusty Kuntz was named special assistant to the general manager and will report Thursday to the instructional league in Surprise, Ariz., where he will work with outfielders and baserunners. Mike Jirschele, who has managed the Royals Triple-A Omaha affiliate the past eight seasons, will be the 1B coach the remainder of the season. Rain delayed the start of the game for 1 hour. A's 1B Daric Barton walked in the third, his major league-leading 101st.