Colon (1-4) fell behind 5-0 before recording an out, but he came back to send down 13 of the next 14 batters faced. Reddick hit a home run -- the 100th of his career -- to push the Houston lead to 6-0 in the fifth.
"Just in the first inning, typical to the game plan, I was throwing a lot of fastballs, and they're real good hitters," said Colon, who took his first loss at Houston in 13 career starts. "They were prepared and jumped on them."
"We did a great job of getting into the game, obviously," Astros manager A.J. Hinch said. "Five really good at-bats, especially early. ... It was a big inning for us, and arguably our best inning to start a game."
Astros starter Charlie Morton (4-2) cruised into the sixth before his command betrayed him. Matt Kemp and Nick Markakis had RBI singles in the sixth, and Morton was pulled after he walked Dansby Swanson with the bases loaded to get the Braves to within three runs, 6-3.
MOMENTS THAT MATTERED Devo to the rescue: When Morton slowed in the sixth, Hinch summoned versatile reliever Chris Devenski to stop the momentum. Devenski fell behind Santana 2-0 but came back to strike him out swinging to end the threat and strand the bases loaded.
"He's been remarkable," Hinch said. "I'm trying not to pitch him too much. He's a guy that will always take the ball, he's a guy I can put in any situation and he's ready from the start to the finish of the game. Very rarely do you have a reliever I literally could call down in the third if I needed to and would trust that he would be prepared mentally to pitch, or he has closed the game for us. He never ceases to amaze."
Correa goes way deep: Correa's three-run home run in the first inning was the second by an Astros player this year to strike the new batter's eye in straightaway center field. The ball traveled 438 feet, which is two feet longer than the distance to center field was prior to this season. The ball came off the bat at 106.5 mph, according to Statcast™.
"I didn't know it was going to be out," Correa said. "You never know with this ballpark when the roof's open. I hit a couple of balls with the roof open I thought were gone and they're not, so I started running like it was a double and obviously when it hit the wall I started jogging, realizing it was a homer."
"He can take the day off tomorrow and follow suit with a game like today's, and get out of town." -- Hinch, on Braves star Freddie Freeman, who went 0-for-4 with three strikeouts
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Beltran's double in the sixth was his 544th and ties him with Derek Jeter for 31st all-time.
Atlanta center fielder Ender Inciarte nearly made a play on Alex Bregman's sixth-inning triple that extended Bregman's hitting streak to 10 games, most by an Astro this season. It had a 77 percent hit probability, according to Statcast™, and there was a 60 percent catch probability for Inciarte on the well-struck ball to deep right-center, which would have been a tough 3-star catch. Inciarte was 4-for-4 on 3-star opportunities coming into the game.
WHAT'S NEXT Braves: Left-hander Jaime Garcia makes his sixth start of the season Wednesday to conclude the two-game set, with first pitch scheduled for 2:10 p.m. ET. Garcia has a career 63-46 record but is 3-6 with a 6.40 ERA against Houston.
Astros: Right-hander Joe Musgrove (1-3, 5.40 ERA) will take the mound at Minute Maid Park on Wednesday at 1:10 p.m. CT. Musgrove, who has never faced the Braves, is 3-4 with a 3.04 ERA in 10 career games at home (nine starts).