Wilmer Flores hit an RBI single with two outs in the ninth inning and the San Francisco Giants beat the Seattle Mariners 5-4 on Sunday to sweep the three-game series. Mike Yastrzemski hit a three-run homer for the Giants, who are 8-1 and off to their best start since 2003. Randy Arozarena tied it at 4 for the Mariners in the ninth with an RBI double after Seattle was down to its last strike against Giants closer Camilo Doval (1-0).