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In a highly anticipated meeting between a pair of AL East rivals preparing for a stretch run, the Yankees got more shoddy work from their bullpen and made four errors in a 6-3 loss to the Red Sox to open their homestand Thursday night.

The defensive miscues led to three unearned runs — with three of the errors coming in an unwatchable second inning.

And while they’ve gotten accustomed to shaky bullpen work — even after they tried to bolster it at the trade deadline — the reliever that gave up the go-ahead run on Thursday, Luke Weaver, was an unlikely candidate to falter.

The right-hander has been superb for much of the season, so when he entered in the top of the seventh and immediately allowed a single to Trevor Story and an RBI double to Nathaniel Lowe, it stunned the sellout crowd in The Bronx.

And the Yankees, who’d tied an MLB record by hitting 14 homers over their previous two games, came up empty to open this series to snap a five-game winning streak.

This one had a bit of the feel of Yankees-Red Sox games of years past, with the teams vying for a playoff spot — and playing an interminably long game.

Unlike the old days, they aren’t battling for AL East supremacy.

Instead, they’re both still chasing Toronto for the division lead.

And with Thursday’s loss, the Yankees have lost six of seven meetings against the Red Sox this season.

Boston, which entered having dropped three in a row, closed to within a half-game of the Yankees in the wild-card standings.

The Yankees also wasted another strong outing from Luis Gil, who gave up just one earned run in five innings, pitching out of trouble throughout his outing.

Gil survived a shaky first inning, getting out of it unscathed despite a pair of walks.

In an unsightly third inning, the Yankees made three errors.

Gil made a fielding error on a Masataka Yoshida comebacker to open the second and Jazz Chisholm Jr. followed with a throwing error on what should have been a double play, which allowed Ceddanne Rafaela to get to second.

And only a diving play by Ryan McMahon at third prevented a Ben Rice throwing error on Rafaela’s steal of third.

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The sloppiness continued when Rice then threw the ball into center field on David Hamilton’s swipe of second — which allowed Rafaela to score the game’s first run.

Boston followed with a mistake of their own, as Gil picked off Hamilton at third.

Rice tied the game with a leadoff homer into the bleachers in right field in the bottom of the inning.

Gil escaped trouble again in the third, pitching around a double by Alex Bregman to open the inning.

The Yankees took the lead in the fourth, as Chisholm singled, stole second and got to third on a throwing error by Carlos Narvaez on the play.

With the infield in, Paul Goldschmidt singled to center to make it 2-1.

Boston loaded the bases with no one out in the fifth.

Gil recovered to give up just a sacrifice fly to Lowe.

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The Yankees went up again in the bottom of the inning on Chisholm’s RBI single, a pop fly to shallow center that Trevor Story couldn’t catch.

It scored Aaron Judge from second.

Goldchmidt walked to load the bases for McMahon, who struck out.

Camilo Doval’s struggles since joining the Yankees continued, as he gave up the tying run in the sixth.

Then, the typically reliable Weaver gave up a leadoff single to Story and a go-ahead double to Lowe.

He left with the bases loaded and two outs and Tim Hill came in and got Roman Anthony swinging to keep it a one-run game- and leaving the Red Sox just 2-for-16 with runners in scoring position.

Rice did more damage in the seventh, with a one-out triple off ex-Met Steven Matz.

But Chisholm struck out and Goldschmidt popped out to strand Rice at third.

After a Goldschmidt error, Yerry de los Santos gave up a two-run shot to Anthony.