KANSAS CITY, Mo. (AP) -

       Rick Porcello cruised through seven innings, the Tigers battered James Shields once again and Detroit rolled to an 8-2 victory over the Royals on Friday night to open their three-game set.
 
      Victor Martinez had a pair of doubles and drove in two runs, and J.D. Martinez and Alex Avila also drove in two runs apiece as the Tigers won their fourth straight against the Royals.
 
      Porcello (4-1) continued what has been the best start to a season in his career, giving up a sacrifice fly to Eric Hosmer, a solo homer to Billy Butler and little else. Porcello allowed four hits while striking out six without a walk.
 
      Meanwhile, Shields (3-3) allowed eight runs - seven of them earned - on 12 hits, a walk and a hit batter in 6 1-3 innings. It was the worst outing for the Royals ace since last September.