DENVER — Germán Márquez came out of the gates firing this season.

He tossed out seven innings in his first start, giving up just one run on three hits against a jam-packed Dodgers lineup. His fastball was crisp that day, his changeup finally effective. It seemed as though he was poised to have a career year.

Things have only gone downhill since then. And on Tuesday, things hit a new low: he was nicked for seven runs on a season-high 10 hits as the Nationals beat the Rockies 10-2 to start the three-game series.

Márquez entered the season expected to be the Rockies’ star, ready to fully earn the responsibility of ace after flirting with the title a year ago. His stats so far though have been gruesome: he’s allowed 38 hits through his first five starts of the season, the most by a Rockies starter through their first five starts of the year since Chris Rusin allowed 41 in 2016. Márquez’s 6.92 ERA is the second-highest in MLB, and his highest since the beginning of the 2017 season, when he was still a rookie figuring things out in the major leagues.

His stuff is moving the same as usual. His velocity is normal. His breaking ball has been consistent. So what’s been the problem? His fastball command, but, maybe more importantly his mental state. Manager Bud Black has noticed his concentration has been off, and that he’s not being as aggressive as he needs to be in spots.

Márquez said he thinks that’s not the issue, and that it’s mainly mechanical, but added that he needs to control his game better and not rush. He feels his best when everything is working for him, and right now it’s only that slider that’s on his side.

“My focus has been the same,” he said. “I’m going out there to give it my best to win the ball game. I don’t want those games. … it’s not working well. It happens. I need to keep going.”

His catcher, though, has noticed one other notable thing.

“For me, it’s the confidence,” Elias Díaz said. “He needs one or two good starts and we’ll get back to it.”

On Tuesday, Márquez’s night kicked off on a bad note, walking Cesár Hernández on five pitches, all fastballs. A double play — Colorado’s league-leading 32nd of the season — got him out of the second, but he gave up a hit and hit a batter to open the third. Then he sent a fastball over the plate to the red-hot Josh Bell, who launched a home run off him into left field to give the Nationals a 3-0 lead.

Márquez’s night didn’t get any better from there, giving up another run in the fourth and three more in the fifth. There were signs, though, that this was coming. He had the best stretch of his career last June to July, almost throwing a no-hitter and making his first All-Star team. But sandwiched in between that period was a bad start and a worrisome end. He had a 6.12 ERA in his final 13 games, only getting through six innings three times in his last nine starts.

“It’s frustrating,” he said. “I want to throw good games. I have to keep the ball down and keep working.”

On Tuesday, Márquez didn’t get any help from the offense, either. Nationals starter Erick Fedde stumped them, giving up just one run. Fedde was effective all night, tossing out 102 pitches in seven innings. CJ Cron hit his ninth home run — tied for the most in MLB with Aaron Judge and Anthony Rizzo — in the eighth off of reliever Erasmo Ramírez, but by then it was too little, too late to make any difference in the score.

“We couldn’t get to his stuff,” Black said. “He pitched pretty good.”