SAN FRANCISCO -- When his teammates started debating after the game whether his second-inning blast into the San Francisco Bay qualified as one of AT&T Park's "Spash Hits," Kansas City Royals slugger Mike Moustakas shied away from the discussion.

"They all count the same," he insisted after he'd contributed the longest of his team's three home runs to a 7-2 win that completed a two-game sweep of the struggling Giants on Wednesday afternoon.

"I'm happy when they get over the fence," Moustakas said of his 18th home run, a solo shot against former teammate Johnny Cueto. "Regardless of how far they go."

Moustakas, Jorge Bonifacio and Lorenzo Cain each belted a home run in a 16-hit attack that backed the strong pitching of right-hander Jason Hammel. The victory was the Royals' third in four interleague meetings this season with the team that defeated them in the 2014 World Series.

"I left those three pitches hanging and they beat me," Cueto said afterward. "I just had a bad game."

In beating the Giants for first time in 13 career meetings, Hammel scattered eight hits in 6 2/3 innings. He walked one and struck out four, pitching Kansas City to its fourth straight win.

"Real nice. Hasn't happened much this year," Hammel said of the offensive support. "Anytime you get runs to work with, you want to make them count."

Hammel (3-6) pitched with a lead after Moustakas crushed a Cueto pitch well over the right field wall leading off the second inning. The homer hit a railing along a walkway beyond the wall and one-hopped into the San Francisco Bay, thus preventing it from becoming what would have been the first "Splash Hit" in Royals' history.

The homers by Bonifacio and Cain came back-to-back in the third inning. Bonifacio's ninth was a two-run shot that also plated Whit Merrifield, who had singled, and Cain followed two pitches later with his seventh of the season, increasing the Kansas City lead to 4-0.

The back-to-back homers were the fifth of the season for the Royals and second of their five-game Western swing. Eric Hosmer and Salvador Perez hit consecutive homers Saturday in San Diego.

"That's what we planned coming out of spring training," Royals manager Ned Yost said of a deep offensive attack that featured two or more hits from six different players. "We knew if we stayed calm, didn't panic, we'd be all right. This is the offense we knew we had."

The Royals knocked out Cueto in the sixth with an RBI double by Bonifacio after another single by Merrifield.

Cueto (5-6) gave up five runs and a season-high 10 hits in 5 2/3 innings. He walked three and struck out five.

"This is humbling to go through something like this," said Giants manager Bruce Bochy, whose team completed a 1-4 homestand. "It's a tough time for these fellows."

Alcides Escobar, Cain and Merrifield, who scored three times, finished with three hits apiece the Royals, who have totaled 38 runs in opening their nine-game trip with four wins in five outings.

Kansas City opens a four-game series against the Los Angeles Angels on Thursday.

Bonifacio recorded three RBIs, and Moustakas and Cain drove in two runs apiece for the Royals, who improved to 4-1 in interleague play this season.

Denard Span, Eduardo Nunez and Joe Panik had two hits apiece for the Giants, who lost for the seventh time in their last eight home games and 11th time in their last 15 games overall.

The Giants totaled 10 hits.

NOTES: Royals 3B Mike Moustakas has hit safely in 12 of his last 13 games, going 19-for-50 (.380) over that stretch with five homers and 14 RBIs. ... Moustakas' 18th home run of the season got him halfway to 1B Steve Balboni's club record of 36 set in 1985. The Royals won't reach the midpoint of the season until July 2. ... Kansas City's pitchers recorded an 0.95 ERA in four games against the Giants this season. ... Royals SS Alcides Escobar's bad throw in the ninth inning ended Kansas City's four-game errorless streak. The Royals have committed a major-league-low 22 errors this season. ... The back-to-back home runs allowed by Giants RHP Johnny Cueto were the ninth of his career. He's allowed two or more home runs in a game 39 times. ... The Giants have allowed 10 or more hits in a game seven times this season, tied with the Pittsburgh Pirates for the most in the majors.