Tigers 9, Royals 2: Drew Smyly dominated through seven scoreless innings and Nick Castellanos drove in three runs as visiting Detroit won its fourth straight.Torii Hunter slugged a late three-run homer while Miguel Cabrera and Ian Kinsler had two hits and an RBI apiece for the Tigers, who have also won four in a row versus Kansas City. Smyly (2-1) allowed two singles and two walks while striking out six in the longest outing of his career.Danny Duffy (1-2) allowed a run and two hits with four walks in four innings in his first start of the year after six appearances out of the bullpen. Eric Hosmer had two hits and Billy Butler and Alex Gordon collected RBIs in the ninth inning for the Royals, who have scored seven runs during a three-game losing streak.Cabrera drew the first of three walks against Duffy in the fourth before Castellanos brought him in with a fly to left to start the scoring. Castellanos went the other way for a two-run double in the sixth to make it 3-0 and Detroit put it away with six in the ninth.Danny Worth had an RBI double for a 4-0 lead, Kinsler lifted a sacrifice fly to center and Cabrera made it a six-run margin with a run-scoring base hit. Hunter later slugged his fourth home run of the season with two on as the Tigers secured their most lopsided win of the year.GAME NOTEBOOK: Smyly is 3-0 versus Kansas City and 12-4 overall in his career. ... Tigers DH Victor Martinez had two hits and two walks in five plate appearances to bump his average to .326. ... Royals RH Aaron Brooks was charged with six runs and seven hits in two innings in his first career appearance.