If momentum really did exist in baseball, it wouldn’t carry over to the back end of a doubleheader.

Outstanding starting pitching and two grand slams hoisted the Orioles to a decisive win in Game 1, but they were down six runs by the second inning in Game 2 and settled for a split after a 11-5 loss to the Astros before an announced 26,586 at Camden Yards.

The Orioles have been .500 nine times this season but never more than two games above .500. Their record fell to 15-16 with a four-game series looming in the Bronx.

Inserted into the rotation after Dean Kremer suffered a strained quadriceps, Brandon Young allowed seven earned runs and 10 total over four innings to raise his ERA from 2.53 to 6.14.

“He just left a lot of stuff out over the plate, and they didn’t miss it,” said manager Craig Albernaz. “Execution was something that was eluding him tonight, and they didn’t miss anything out over the plate.”

Houston sent nine batters to the plate in the top of the first inning and built a 5-0 lead. Dustin Harris had a two-out, two-run single, Yainer Diaz reached on an infield hit on a ball that Jeremiah Jackson couldn’t backhand, and Cam Smith launched a 414-foot three-run homer to center.

Yordan Álvarez hit a 424-foot shot to center with one out in the second to bring Young within a run of tying his career high. He allowed seven runs twice last season, including Aug. 21 against the Astros.

The bases were loaded with one out in the fourth after a walk, error charged to Jackson that should have gone to Weston Weston on the throw, and another walk. What followed were back-to-back RBI singles by Isaac Paredes and Christian Walker, a Harris sacrifice fly and Diaz’s RBI single for a 10-0 lead.

The Astros again sent nine batters to the plate. They already had 10 hits. They were venting.

“It’s part of the game,” Jackson said. “There’s a lot that happened. I take a lot of the blame I guess in a way. Those errors can’t happen. But it’s kind of part of the game, I guess. Try to move on to the next game.

“It’s just more so just getting back to the basics and fundamentals. A lot of the errors, at least speaking for myself anyway, are a lack of concentration. A lack of fundamentals. Really, just kind of getting back to the basics and making the routine plays routinely.”

Defensive breakdowns remain an issue with a team that puts a tremendous amount of emphasis on glove work.

“To me, it’s just consistency,” Albernaz said. “I think anyone that watched the first game, I would say our defense was pretty good, if not really good. Yeah, the second game was just ugly. Like, that’s unacceptable. I know it’s a doubleheader, it’s tough to win one game in the big leagues, never mind two on the same day. But we didn’t give ourselves a chance to win this game.

“It’s constant conversations. The guys acknowledge it. Guys are working every day. That’s something that (we’re) looking to continue to get better at.”

Young is the 12th pitcher in Orioles history to allow 10 or more runs in a game, and the first since Andrew Cashner, in only 1 2/3 innings, against the Rangers on Aug. 2, 2018. All 10 of Cashner’s runs were earned.

“It was just one of those days,” Young said. “Got my butt kicked. Not much I can say. It sucks. I thought I turned a page from last year, not having these kind of blow-up outings, but yeah, it’s just disappointing to the team, trying to go for the sweep and we’re in a 5-0 hole in the first. It’s just really frustrating.”

Not having early fastball command or getting chase with the splitter sabotaged Young’s outing.

“I think after that, just falling behind and getting into bad spots, and then throwing them over the middle of the plate,” Young said. “They’re a good-hitting team. Kudos to them. But like I said, just super frustrating.

“I’ll look at it today and then I’ll try to flush it after that. Kind of going back to last year having some of these, it’s like fast-tracking, kind of, forgetting about it, the better. I’ll dive into it, see what’s going on. See if I was tipping. See if I was just falling behind and leaving them in the middle of the plate. I think it was a combination of all that, so yeah, try to forget about it pretty quickly.”

Cam Foster entered in the top of the fifth inning and a run scored on his second wild pitch. He stranded two in the sixth.

The Orioles didn’t have a hit in Game 1 until two outs in the fourth inning, and Lance McCullers Jr. kept them hitless until Pete Alonso’s RBI double with one out in the fourth after Taylor Ward drew the third of his five walks in the doubleheader.

Tyler O’Neill walked for the second time in Game 2 and Leody Taveras followed with a two-run triple, his first three-bagger this season and the 13th of his career.

Bryan Abreu replaced McCullers in the seventh and the Orioles tried to chip away at Houston’s lead. Gunnar Henderson had a run-scoring double with one out and the bases were loaded after another Ward walk, but Dylan Beavers and Coby Mayo struck out. Mayo had replaced Alonso at first base.

Mayo had a sacrifice fly in the ninth to score Colton Cowser, who walked after pinch-hitting for Ward.

Keegan Akin tossed a scoreless seventh. Tyler Wells stranded a runner in the eighth. Yennier Cano retired the side in order and struck out two in the ninth to lower his ERA to 1.69.

Samuel Basallo caught Game 2 and struck out four times after collecting 11 hits in his previous 20 at-bats.

The Orioles were outhit 27-12 in the doubleheader.

A starter still hasn’t been named for Friday night.