NEW YORK -- Aroldis Chapman stood near the back of the mound on Sunday, watching as two outfielders pursued a drive destined to land in the Yankee Stadium visiting bullpen. The Yankees’ closer pinned his arms atop his head, his grimace clearly telegraphing the dismay of yet another ineffective appearance.

Pete Alonso launched a game-tying home run off Chapman and José Peraza smacked a two-run, fan-interference double as part of a six-run seventh inning as the Yankees absorbed a crushing 10-5 defeat in the opener of Sunday’s split-admission seven-inning doubleheader at Yankee Stadium.

• Box score

“We know that we haven't been playing our best,” Yanks catcher Kyle Higashioka said. “We're doing everything we can possibly do to try to turn it around. It doesn't look good out there on the field, but I just know we're all working as hard as we can to turn it around.”

Chapman faced three batters and retired none before handing the ball to Lucas Luetge. Peraza’s go-ahead hit was snagged by a young fan hanging over the left-field wall, prompting a brief discussion among the umpires. Brandon Nimmo added a two-run single and Francisco Lindor also knocked in a run as the Mets batted around in the nightmarish frame.

“It’s another awful loss,” Yankees manager Aaron Boone said. “There’s no other way to put it. The bottom line is that we’ve got to have broad shoulders in there. This one is unique in that we’ve got another game right now and we’ve got to get over this. It’s really freaking hard right now. We’ve got to go compete our [butts] off right now.”

Saddled with their seventh loss in eight games, the Yankees fell to 41-41. Gerrit Cole ran out of steam earlier than expected, tagged for four runs and six hits before being lifted with one out in the fourth. The ace heard boos from an announced crowd of 42,714.

“It is what it is,” Cole said. “You sign up for it when you come here. It’s not a good feeling. You just try to pitch well enough so that doesn't happen.”

Cole has allowed 10 runs (nine earned) over his past two outings against the Red Sox and Mets. The right-hander pitched to a 2.33 ERA across his first 15 starts.

“I look at Gerrit today and he had the swing-and-miss there,” Boone said, alluding to the 13 swing-and-misses that Cole generated. “I think they just did a really nice job of laying off some pitches on the margins of the zone. They made him work so hard, and that’s what got to him.”

Alonso’s game-tying home run came on a 1-2 slider from Chapman, which Boone said that he thought was the incorrect pitch to throw in that spot. Higashioka accepted responsibility for that call, saying, “That’s on me. We shouldn’t have thrown that.”

In a bizarre twist, Chapman and Cole were both announced as American League All-Stars minutes after the final out of Sunday’s first game.

“We can’t get where we want to go without those two guys,” Boone said.

Boone said that he will “continue to talk through” Chapman’s hold on the closer’s role. Boone said that he opted not to continue with right-hander Chad Green, who threw two pitches in the sixth inning, because he wanted to ensure Green would be available for the second game.

“We’re kind of piecing today together a little bit,” Boone said. “I felt confident in Chappy coming in.”

The Mets struck first, with Dominic Smith lifting a solo home run to the right-field short porch in the first. Cole permitted two walks and a single to load the bases in the fourth, then Tomás Nido and Nimmo stroked run-scoring hits before Lindor greeted reliever Jonathan Loaisiga with a game-tying RBI single.

An error by Lindor keyed the Yankees’ three-run second, as the Mets shortstop flubbed a potential double-play ball. Facing right-hander Marcus Stroman, Higashioka sliced a two-run double to left field and Tim Locastro lifted a sacrifice fly in his first plate appearance since being acquired from the D-backs earlier this week.

“We have the talent in the room,” Cole said. “We need to continue to fight. Anything is possible.”