KANSAS CITY, Missouri — Mookie Betts is pretty good against Danny Duffy. Betts hit a two-run homer off Duffy in a four-run third inning and the Boston Red Sox defeated the Kansas City Royals 7-5 Thursday to complete their first series sweep in nearly a month. Betts is 7 for 11 with five home runs against Duffy (3-3). “I put some good swings on some good pitches,” Betts said. Betts has six hits, five home runs and a walk in his last seven plate appearances against Duffy. “I’ve got to a better job of not serving it to him on a platter,” Duffy said.