Royals 12, Diamondbacks 2: Norichika Aoki hit his first career grand slam and Billy Butler and Salvador Perez added three-run shots as visiting Kansas City routed Arizona in the opener of a three-game series.

Butler had a season-best four hits and Perez added three as the Royals remained 4 1/2 games behind first-place Detroit in the American League Central. Kansas City, which had 15 hits and recorded a season high for runs, trails Toronto by a half-game in the chase for the AL’s second wild-card spot.

Danny Duffy (6-10) struck out seven and allowed one run and three hits in five innings to win for only the second time in nine starts. Diamondbacks starter Wade Miley (7-8) was charged with 10 runs and nine hits in 4 2/3 innings.

Arizona’s Mark Trumbo had a run-scoring single in the first inning before Kansas City moved ahead on Perez’s three-run shot to left-center field in the third. Butler hit his blast over the left-center field fence during an eight-run, fifth-inning uprising to make it 6-1 and Alex Gordon scored on a wild pitch later in the inning.

The Royals followed by loading the bases against Miley before Bo Schultz entered and Aoki responded with his first homer of the season to make it 11-1. The Diamondbacks added an eighth-inning run on an infield out by Didi Gregorius before Kansas City’s Lorenzo Cain hit a sacrifice fly in the ninth.

GAME NOTEBOOK: Gordon singled to left field in the fifth to become the 10th player in Royals history to reach 1,000 career hits. … Miley has allowed 20 homers, one shy of his career-worst total of last season. … Butler has posted four or more hits on 15 occasions.