From the second batter on, things were off for Dean Kremer.

A first-pitch homer by Michael Busch put the Chicago Cubs ahead 1-0, and Kremer and the Orioles were never able to keep up. The Cubs led the entire time as they won the first of a three-game series 9-2.

This was Kremer’s second start back after missing just over a month with a right triceps strain. His first on July 3 was much smoother — five innings with just two hits and zero runs against the Seattle Mariners. The form he showed that day didn’t carry over to Tuesday.

“He just wasn’t as sharp as he was in that outing against Seattle,” manager Brandon Hyde said. “He gave up the homer to Busch and didn’t get hit real hard, a lot of miss-hits and fortunate breaks, I thought, for them. He had the split going really well in Seattle. I think that was really inconsistent, the fastball just didn’t have the same amount of life that he had, was kind of searching up there.”

While he escaped the first with just the solo home run, his next three innings dragged on as the Cubs tacked on runs. Chicago scored one in the second, then two in the third as a series of defensive errors from Gunnar Henderson and Ramon Urías kept the inning going.

It was the fourth where things really got out of hand for Kremer. He hit Nico Hoerner, despite being ahead in the count, to open the inning, then gave up a single to Busch to put two runners on. After securing two outs, Kremer was just one strike away from ending the fourth when Ian Happ hit a three-run home run. Kremer said he thought he could outsmart him by placing the ball up after going down and away on the prior pitch.

“They are a good contact team and they got a piece of pretty much everything,” Kremer said.

Kremer completed the inning, but that would be it for the day after he allowed seven runs, five of them earned. He also walked three, including Cubs third baseman Miles Mastrobuoni, who entered the game hitting .145, twice.

It was a poor outing in what has been an inconsistent season for Kremer. He has performed well at times, allowing one run or less three times, including a game where he pitched a season-high seven innings. But he has also now allowed five or more earned runs in three of his 11 starts, the other two times also coming against the National League Central.

A performance like this, after the struggles of Cole Irvin and the eight-run, one-inning start Cade Povich had last week, underscores the Orioles’ need to acquire more pitching at the trade deadline. Due to the injuries in their rotation — Kyle Bradish, John Means and Tyler Wells all had season-ending elbow injuries — Kremer is now the Orioles’ No. 3 starter. If the playoffs started tomorrow, he would likely be the one they sent out in Game 3. He filled that role last year, when he allowed six runs in 1 2/3 innings as the Rangers eliminated the Orioles.

Baltimore’s offense didn’t have many answers for the Cubs’ pitching staff, scoring just two runs off starter Jameson Taillon. Jordan Westburg, who was named as an All-Star just prior to the game, hit a solo home run in the second.

“I was still a nervous wreck,” Westburg said. “The news hit pretty hard, it’s a whirlwind getting texts and trying to coordinate plans for family and friends. To be able to slow the game down and have a big moment like that, I know ultimately we lost the game, which is never good, but that was a pretty cool moment.”

In the third, Henderson opened the inning with a single and advanced to third on a base hit from Adley Rutschman. Henderson scored when Anthony Santander grounded into a double play.

Correction: This story has been updated to correct the spelling of Michael Busch’s first name.