Tigers 5, Royals 1: J.D. Martinez and Alex Avila each homered and Rick Porcello tossed seven strong innings as visiting Detroit extended its winning streak to five games.

Porcello (12-5) allowed one run on six hits and Martinez recorded three hits for the Tigers, who increased their lead over the Royals in the American League Central to 7 1/2 games. Austin Jackson, Ian Kinsler, Torii Hunter and Avila added two hits apiece to help Detroit improve to 6-0 this season in Kansas City.

Kinsler gave the Tigers an early lead with an RBI single in the third off James Shields (9-5), who allowed two runs while striking out eight over seven frames. Omar Infante and Billy Butler each contributed two hits for the Royals, who lost for the sixth time in their last eight games.

The Tigers moved ahead 2-0 in the third as Hunter tripled with one out and scored on Avila’s single to left field. Kansas City loaded the bases with two outs in the fifth before Porcello struck out Lorenzo Cain to end the threat.

The Royals got on the board in the sixth, when Salvador Perez and Infante delivered back-to-back singles with one out and the former scored on Butler’s sacrifice fly. Detroit added three insurance runs against Aaron Crow in the ninth on Martinez’s leadoff homer and Avila’s two-run shot into the right-field seats.

GAME NOTEBOOK: Kinsler’s 115 hits before the All-Star break are the third-most by a Tigers player since 1933. … Shields threw a season-high 121 pitches for the Royals, who have been outscored 49-14 by Detroit in six losses at home this season. … Tigers RHP Joba Chamberlain worked a perfect eighth inning to pick up his AL-leading 18th hold. Chamberlain hasn't allowed a run in 23 of his last 25 appearances.