Gattis continued his impressive power surge this month by yanking a 2-2 fastball from Royals right-hander Jakob Junis (5-7) to center field in the sixth inning, following a succession of singles from Jose Altuve, Carlos Correa and Josh Reddick. Gattis, who added a double in the eighth and finished 2-for-4 with four RBIs and two runs, has recorded seven homers and 22 RBIs in June.

The Astros extended their winning streak to nine games with the power display. Gattis pushed Houston to a 6-3 lead with his 14th home run on the season.

Alex Bregman and Correa launched solo shots off Junis in the fourth inning to erase a two-run deficit. Bregman homered to left for his ninth dinger; Correa cranked a 455-foot shot to left two batters later for his 12th.

The Royals have dropped 11 of 13 games. Right fielder Jorge Soler, third on the team with 28 RBIs, left the game in the top of the seventh after tripping and falling out of the batter's box in the sixth inning. X-rays revealed a fracture of the left first metatarsal in his foot, the Royals announced.

Astros right-hander Charlie Morton (8-1) was the beneficiary of the run support, overcoming a bout of wildness in the fifth inning that included three consecutive walks. Royals third baseman Mike Moustakas forced in Paulo Orlando when he reached via free pass to lift Kansas City to a 3-2 lead. Orlando and Abraham Almonte, who walked for a second consecutive plate appearance after Orlando reached on an infield single, scored in the Royals' two-run third.

With two outs in the third, Moustakas drilled a two-run double to right field that gave the Royals a 2-0 lead. Moustakas finished 1-for-3 with a walk and three RBIs. After issuing the walk that put the Royals ahead, Morton induced an inning-ending double play off the bat of catcher Salvador Perez to limit the damage. Morton returned and recorded two strikeouts in the sixth.

Morton allowed three runs on four hits and four walks with nine strikeouts over six innings. Junis, who fanned Gattis twice before allowing the grand slam, surrendered six runs on seven hits and a walk with three strikeouts over 5 1/3 innings. He allowed at least three homers in a start for the fourth time this season.

--Field Level Media