Kole Calhoun hit the ball hard to places normally left unintended that turned into outs, including one huge double play. Jason Grilli, who has been effective out of the bullpen, gave up two runs in the sixth inning that led to the Angels dropping the opener, 5-3 to the Oakland Athletics, of an important three-game series between the top two contenders in the AL West. Grilli (1-2) took over because Santiago, who allowed two runs — one earned — on seven hits in five innings, lost the feel on his offspeed pitches as a result of Craig Gentry's ball that clipped him en route to an out. Erick Aybar's wild throw into the A's dugout allowed the tying run to score in the fifth. Calhoun, throw out to open the game on a ball fielded by the second baseman in shallow right field, lined into a double play to end the fifth after the Angels put runners on second and third. Mike Trout and Josh Hamilton each hit home runs and David Freese singled home a run in the ninth before Chris Iannetta struck out with the bases loaded to end the game. Angels: RHP Garrett Richards underwent surgery to repair the torn patellar tendon in his left knee.