"I knew I hit it pretty good, but that fence out there is pretty tall," the Los Angeles born-and-bred slugger said.
Although this group of Royals only has two crazy games of playoff history, it's becoming clear that good things happen to Kansas City in October.
The Royals went a few more extra innings, withstood a few more scares and figured out another dramatic way to win a playoff game — thanks to the local boy.
Moustakas homered leading off the 11th, and the Royals kept rolling in their first post-season in 29 years with a 3-2 victory over the Los Angeles Angels in their AL Division Series opener Thursday night.
Kansas City had managed just two baserunners since the fifth inning when Moustakas hit the first extra-inning homer in post-season history for the Royals, a high shot off Fernando Salas that barely reached the elevated right-field stands at Angel Stadium.
"It's probably the biggest one I've ever hit so far," said Moustakas, who had dozens of friends and family members in the Royals' tiny cheering section. "It felt really amazing."
Game 2 in the best-of-five series is Friday night at the Big A, with Angels 16-game winner Matt Shoemaker taking on fellow rookie Yordano Ventura.
Alcides Escobar had an early RBI double for the Royals, and their bullpen repeatedly escaped trouble in Kansas City's first game since that spectacular, 12-inning comeback victory over Oakland in the wild-card playoff Tuesday night at Kauffman Stadium.
Chris Iannetta and David Freese homered early in the Angels' first playoff game since 2009, but the majors' most productive offence stranded eight runners in the five innings before Greg Holland's perfect 11th.
"This is the type of game that we play," Royals manager Ned Yost said. "We don't score a bunch of runs ... so we have a lot of confidence in our pitching."
Winning pitcher Danny Duffy worked the 10th for Kansas City, and Holland picked up the save after arriving at the ballpark around the fourth inning. He went to North Carolina on the Royals' off day to attend his child's birth.
Mike Trout was 0 for 4 with a walk in his playoff debut. The favourite for AL MVP grounded into a fielder's choice in the 10th before Albert Pujols popped out to end his 0-for-4 Angels playoff debut.
Josh Hamilton popped up to end the game, capping his 0-for-5 return to the lineup.
"We had some guys in scoring position, just couldn't get that one hit, especially late," Angels manager Mike Scioscia said. "Those guys hung in there and got the big outs and got the big hit late. So we hit two home runs to keep ourselves in the game, but outside of that, we didn't really pressure those guys very much."
Jered Weaver, Joe Smith and Huston Street combined to retire Kansas City's final 15 batters before extra innings — and that's when the Royals went to work. Kevin Jepsen let two runners on in the 10th, but retired Salvador Perez and Omar Infante to escape.
Salas wasn't as lucky, giving up a homer to a third baseman who grew up in the San Fernando Valley before making his big league debut and hitting his first homer in Anaheim three years ago.
A raucous crowd banged balloons and cheered on the Angels throughout their post-season return after a half-decade away, but the fans got tense while the teams managed just three hits apiece in the first nine innings. Los Angeles earned home-field advantage throughout the post-season with a big league-best 98-64 record.
The Royals can't match Los Angeles' lineup on paper, but they've got some remarkable post-season mojo.
Even before Moustakas' homer, Nori Aoki made dramatically awkward catches on the right-field warning track to end the sixth and seventh, twice making up for poor routes to the Angels' drives with a last-instant stab. Lorenzo Cain also made two exceptional plays in centre field in the first two innings, underlining Kansas City's stellar defence.
"Lorenzo Cain is one of the best centre fielders in baseball, and Aoki made some unbelievable plays," Moustakas said. "We were able to cut their rallies down a little bit on some of the huge catches there in right field and centre field, and hats off to those guys."
Weaver yielded three hits over seven strong innings for the Angels while Jason Vargas, his good friend and Long Beach State teammate, pitched six innings of three-hit ball for Kansas City.
Royals: RHP Kelvin Herrera walked Freese on five pitches leading off the seventh and then left the game with right forearm tightness. Herrera, a key member of Kansas City's vaunted bullpen, will be re-evaluated Friday.
Angels: Hamilton played left field and batted seventh after missing 21 of the Angels' final 22 regular-season games with upper-body injuries.
Shoemaker (16-4, 3.04 ERA), the 28-year-old rookie who gets credit from Scioscia for saving the Angels' season, makes his playoff debut. He hasn't pitched since Sept. 15, when he strained an oblique muscle. Kansas City counters with Ventura (14-10, 3.20), who struggled in the sixth inning of the wild-card game, but possesses a 100 mph fastball.