"Every ball that was hit made the right sound and it hit the barrel," Moss said. "I hate to be the guy that's always complaining, but if you hit a ball like that, like we hit tonight, they should go over the fence. It's good to see us get rewarded for those, because sometimes here you don't."
Holliday started the power display with a three-run blast in the first to give the Cardinals a 3-0 lead. He made Reds starter and local product Tim Melville pay for walking Matt Carpenter and Jeremy Hazelbaker to start the inning.
"Obviously, he was having a hard time finding the strike zone," Holliday said. "You take until you get a strike, and then you get aggressive with him."
Diaz hit a three-run homer in the third to make it 7-3. The blast came at a critical time as Joey Votto had hit a three-run homer in the top of the frame to get the Reds back into the game.
"You could have a serious momentum shift when you go 4-0, and all of a sudden you're 4-3 and the other team is feeling real good about themselves," Cardinals manager Mike Matheny said. "A beautiful swing that Diaz put on that ball."
Holliday hit a 449-foot shot to dead center in the sixth. He entered the game hitting just .188 but raised his average to .235 by going 2-for-2.
"He's been hitting the ball well, though," Moss said. "Obviously he's 20 or 30 at-bats into the season and he hasn't got as many hits as he'd probably like, but he's been squaring some balls up. Today he elevated them and they went 400-and-whatever feet."
Grichuk hit his second homer is as many days in the seventh, and Moss and Adams hit the fifth and sixth pinch-hit homers, respectively, for the Cardinals this season. The team had four home runs off the bench in all of 2015.
Last season, the Cardinals hit just 137 homers, which ranked 25th in the Majors.
The six home runs Friday, totaling 2,425 feet, gives the Cardinals 16 in their first 10 games.
"I think we're just swinging at good pitches right now," Adams said. "Balls are up in the zone and guys aren't missing them."
Joe Harris is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.