HOUSTON -- Mike Moustakas has been mired in such a tough start to the season he joked that he tried to do a little something extra to make sure the ball he hit in the 11th inning would carry out of Minute Maid Park.
''I was kind of blowing as it was up in the air, hoping it was going out,'' he said before flashing a huge grin.
Moustakas was hitting .098 before his shot to the seats in right field off Jerome Williams (0-1) to lead off the 11th. A small group of Royals fans stood and yelled `Moooooose' as he rounded the bases after his first homer this year.
''It felt great,'' Moustakas said. ''Slow start or no slow start, it's a big win for us. Anytime we can win on the road it's a big win.''
Manager Ned Yost was happy to see Moustakas score the go-ahead run.
''It was big for Moose to do it for us,'' Yost said. ''He's been working really, really hard and tirelessly getting after it. He just needed a little luck and one good at-bat, and that was it tonight for sure.''
Jarrod Dyson singled and added an insurance run on a fielder's choice.
Danny Duffy (1-0) pitched two scoreless innings for the win and Greg Holland allowed a hit and a walk in a scoreless 11th for his fifth save.
Jason Castro and Marc Krauss both had two-run home runs for the Astros. Heralded Houston prospect George Springer made his major league debut, batting second and playing right field.
The 24-year-old, who hit 37 homers combined in Double-A and Triple-A last season, singled and walked, but struck out with one out and a runner on first in the 11th.
Danny Valencia had a solo homer in the second and Salvador Perez tied it up in the seventh with a two-run single.
The Astros went 0 for 6 with runners in scoring position and left 12 men on base.
Eric Hosmer had two hits for his fourth multi-hit game. He led the American League last season with 60 such games.
Lorenzo Cain and Alcides Escobar singled with one out in the seventh inning and Hosmer walked with two outs to load the bases. A sharp groundball single by Perez off Matt Albers rolled just out of reach of a diving Marwin Gonzalez and into left field to score two and tie it at 4-4.
The homer by Krauss put Houston up 4-2 in the sixth inning.
Alex Gordon drew a one-out walk in the fourth inning before a single by Valencia. Dallas Keuchel plunked Justin Maxwell on the right hand to load the bases and Gordon scored on a groundout by Cain to tie it at 2-2.
Springer got his first major league hit on a dribbler that traveled just a few feet down the third base line with one out in the third inning. His parents were sitting behind home plate and his mother stood up and waved her hands in the air when he reached first base.
''It's always good to get that first one out of the way,'' Springer said. ''I didn't really hit it all that well, but I will take it. Now I can relax, breathe a little bit and just have some fun.''
Castro's opposite field homer to left field followed to put Houston up 2-1.
Valencia's shot to the Crawford Boxes in left field gave Kansas City a 1-0 lead in the second inning.
Springer drew a leadoff walk in the fifth inning, but was caught stealing in a rundown later in the inning.
Hosmer made a nifty play on a grounder Matt Dominguez hit off the end of his bat for the second out in the eighth inning. He grabbed it on the run backhanded and flipped it to pitcher Kelvin Herrera, who was covering first.
Cain was initially credited with a single to start the ninth inning, but Houston manager Bo Porter challenged the call and officials found he didn't beat the throw. ... Right-hander Brad Peacock will take Lucas Harrell's spot in the Astros rotation. Harrell was designated for assignment on Wednesday after starting the season 0-3. ... LHP Bruce Chen has been scratched from Thursday's start for Kansas City because of a sore back. RHP James Shields will start in his place in the finale against Scott Feldman. Chen should be able to start on Saturday.