BALTIMORE – It took David Peterson 90 pitches to weave together a masterpiece at Camden Yards on Thursday, and it took one bad slider from Ryne Stanek to pull the threads loose.

The Orioles pounced on a struggling Stanek in the eighth, as they came from behind to beat the Mets, 3-1, in Game 1 of a doubleheader. The Mets went 1-for-11 with runners in scoring position and left eight on base.

With the Mets up, 1-0, Colton Cowser singled off Peterson to lead off the eighth, prompting Carlos Mendoza to summon Stanek from the bullpen. Orioles interim manager Tony Mansolino then went to his bench for the lefty hitting Gunnar Henderson.

Mansolino won the round.

Henderson uncorked on a hanging, knee-high slider, pulling it 400 feet to right for the go-ahead homer – the second pinch-hit homer for the Orioles this year, and the first of Henderson’s career.

Stanek walked pinch hitter Ryan O’Hearn, induced a groundball out, then walked the next two batters to load the bases for Ramon Laureano, who hit a sacrifice fly to right to make it 3-1. The Mets, intending to throw a bullpen game in the nightcap, stuck with Stanek for one more batter, but the righty walked Tyler O’Neill, forcing Mendoza to go to Austin Warren. Warren got Ramon Urias to pop out to end the eighth.

That inning undid a gutsy performance by Peterson, who no doubt wanted to go as long as he could. After a lackluster June that included three starts where he pitched to a 7.47 ERA, the big lefthander returned to form, holding the Orioles scoreless through seven. He allowed one run on five hits with no walks and six strikeouts over seven-plus innings. It was his second strong start in a row as his ERA dropped to 3.06.

The Mets' sole run came in the fifth, when Charlie Morton issued a leadoff walk to Brett Baty, who then stole second and came home when Tyrone Taylor lined a double to the right-field corner. It was the only run Morton would allow. The righty let up four hits with three walks and four strikeouts over six innings.

Jesse Winker, recently returned from the injured list with an oblique injury, was removed from the game in the fourth with back tightness… The Mets recalled Luisangel Acuna from Triple-A Syracuse and designated Travis Jankowski for assignment. Mendoza said the plan was always to get Acuna consistent playing time at the minor-league level, give him more reps at centerfield, and then bring him back up. “We know how important he is to the ballclub,” Mendoza said. “He got exposure in centerfield…and that will kind of be his role here, playing everywhere.”