"I thought I got mine," Moustakas said. "But all you can do it keep hitting it hard."
Then, they started testing the shorter porches in left and right. Four home runs later, the Royals had rallied to even the series at one game apiece.
The home run parade started when Lorenzo Cain jolted a Jordan Montgomery fastball to straightaway left in the seventh for his second homer this season.
Then Bonifacio, who is enjoying a tremendous start to his rookie season, belted a two-run homer later in the inning for a 3-2 Royals lead. The ball screeched out at 104 mph to the short porch in straightaway right.
"I'm always looking for a fastball," said Bonifacio, who got a fastball from reliever Adam Warren on the first pitch he saw in the seventh.
The Royals continue to be amazed by Bonifacio, who hit his fourth home run in five games and extended his hitting streak to seven games.
"He's swinging the bat well," Royals manager Ned Yost said. "He's covering all pitches well, sliders away, covering all fields. I've been impressed with his at-bats from two Spring Trainings ago. I knew he was close to the big leagues then."
Added Royals starter Danny Duffy, "The kid's been here for 10 years if he's been here a month. He's a fixture in the lineup right now. It's fun to watch his every at-bat."
In the eighth, Whit Merrifield went opposite field to the short porch for his fifth home run of the season. In the same inning, Moustakas sent a high drive down near the right-field pole that appeared to be foul, only to slice back fair.
"I think it did," Moustakas said. "I thought it was going foul then it [sliced] back fair. Pretty weird."
Three of the home runs came off the vaunted Yankees bullpen.
"It's unusual because the [bullpen] has been so good," Yankees manager Joe Girardi said. "They've done the job almost every time that we've called upon them. Tonight just wasn't their night. They all gave up home runs. It's going to happen from time to time."
The Royals considered the homer barrage a bit of justice.
"We just missed a couple of pitches early," Duffy said, "but never count us out. Not this group."
Jeffrey Flanagan has covered the Royals since 1991, and for MLB.com since 2015. Follow him on Twitter @FlannyMLB. This story was not subject to the approval of Major League Baseball or its clubs.