AP photo by David Zalubowski / Atlanta Braves catcher Travis d'Arnaud follows the flight of his grand slam off Colorado Rockies starter Austin Gomber in the fifth inning of Thursday night's game in Denver.

DENVER — Travis d'Arnaud homered twice, including a grand slam, and drove in a career-high six runs as the Atlanta Braves pounced on the Colorado Rockies' struggling pitching in a 13-6 rout Thursday night.

D'Arnaud was 3-for-5 and scored three times as the Braves piled up 18 hits in the opener of a four-game series with the Rockies, who have allowed 39 runs over the past three games. He became the first Atlanta catcher to drive in six or more runs since Javy Lopez in 2003.

"It's amazing we did as well as we did last year when we lost him for 100 games," Braves manager Brian Snitker said of d'Arnaud, who had thumb surgery in 2021 but was back in time for Atlanta's run to the World Series championship. "He's such a settling, calming influence for everybody. When he's out there, everybody trusts him. I know I do."

For the Rockies, C.J. Cron hit his 14th homer of the season, Garrett Hampson also went deep and Charlie Blackmon was 4-for-5 in Colorado's 17th loss in 24 games.

After allowing 26 runs in 19 innings in a doubleheader split Wednesday against the Miami Marlins, the Rockies hoped Austin Gomber (2-6) would give them a long, effective outing. The 28-year-old left-hander instead was charged with a career high-tying nine runs and 10 hits over five innings. He has allowed 15 earned runs in his past two starts.

The tired bullpen wasn't any better, with Ty Blach allowing four runs and seven hits over three innings. The Rockies have given up 51 hits in two days.

"Those guys, there's six of them now, they have to perform," manager Bud Black said of the rotation. "So bullpen sessions, really getting into some of the scouting reports, and it comes down to making pitches. And if you don't, the opposition is going to hand it to you."

D'Arnaud smacked Gomber's changeup to left field for a two-run homer in the third, then pulled his curveball over the wall in the fifth for his second career grand slam to make it 9-1. D'Arnaud, whose most recent multihomer game had been in 2019, entered the night batting .250 with four homers.

"The offense exploded tonight. We had a ton of runs, a ton of hits," d'Arnaud said. "A lot of good at-bats, a lot of battles. We're playing good baseball."

Rookie center fielder Michael Harris II, who made his MLB debut last Saturday, had his first multihit game for Atlanta, going 3-for-5 with a double, an RBI and two runs scored.

Braves starter Ian Anderson (4-3) allowed five runs and 10 hits with nine strikeouts in six innings.

Colorado second baseman Brendan Rodgers doubled in the seventh to extend his hitting streak to 20 games, and Connor Joe doubled twice to push his on-base streak to 29 games.

After not playing Wednesday, Braves right fielder Ronald Acuña Jr. went 2-for-5 with an RBI as the designated hitter. Snitker said it's part of the slow process of recovering from surgery to repair the ACL that the two-time All-Star tore in a season-ending knee injury last year.

"I think he's doing a great job of being forthright with how he feels and not covering anything up," Snitker said.

The Braves, the only team in the majors without a three-game winning streak this year, will try again to accomplish the feat Friday night, when they start left-hander Max Fried (5-2, 3.10 ERA) and the Rockies counter with right-hander Chad Kuhl (4-2, 3.56).