Less than two weeks ago, the Yankees finished off a sweep of the AL Central-leading White Sox. They had won six in a row and looked ready to take off.

Instead, they really never got airborne.

After Saturday night’s dismal 7-3 loss to the Red Sox in The Bronx, the Yankees have lost nine of their last 12 games and have failed to win any of their four most recent series.

Most concerning, they have continued to struggle against AL East rivals. The Yankees now are 14-21 against those teams and 2-4 against the Red Sox and Rays on this seven-game homestand.

“That’s not good,” manager Aaron Boone said. “If we’re going to be the club we expect to be, we need to improve that and turn that around.”

The Yankees couldn’t hold an early lead and one of their strengths — the bullpen — was flattened by Boston. Chad Green was lit up for a season-high four runs in the eighth inning and the offense remained underwhelming, getting a two-run homer from Gleyber Torres and little else.

Giancarlo Stanton heard boos after falling to 2-for-23 with 11 strikeouts since coming off the injured list as the Yankees (31-28) fell to fourth place in the AL East, 5 ¹/₂ games behind the division-leading Rays.

“I know the guys in that room, and we believe we’re too good [for this],” said Boone, echoing a common refrain of his from early in the year. “[We] know that we’re obviously going through a tough stretch, know this is part of it. We’re taking our lumps right now and we got an opportunity to turn it around and at least salvage a series [on Sunday], and that’s what our focus and how we’ll look at it is.”

Enrique Hernandez’s two-out, eighth-inning double off Green started the game-deciding rally. With Rafael Devers in motion, Hernandez turned around a 95 mph Green fastball, lacing it into the left-field corner. Devers came all the way around from first to score what turned out to be the game-winning run.

But Green couldn’t keep it there. Christian Vazquez poked a double just inside the first-base bag to score Hernandez and Bobby Dalbec followed with a monstrous two-run home run that traveled 453 feet according to Statcast.

When Dalbec’s bat contacted the ball, a gasp was heard from the crowd. Boos soon followed, and Green was lifted following his worst outing of the season as his ERA skyrocketed from 1.93 to 3.14.

“Those situations when you have a chance to get off the field you just got to make a pitch,” Green said. “It was just a bad-executed pitch and in a situation like that you just got to execute better.”

The game turned in the sixth. Yankees starter Jameson Taillon was cruising with a 2-0 lead, having allowed just three hits and retiring 10 of 11 batters.

It started with a soft opposite-field single by Alex Verdugo. Xander Bogaerts followed by hitting a catchable drive to deep left. Miguel Andujar, an infielder playing the outfield, couldn’t make the play up against the wall. Devers then pulled the Red Sox even with a single to right — the third two-strike hit of the inning — and Marwin Gonzalez greeted reliever Jonathan Loaisiga with a soft double just past Chris Gittens at first base.

“That sixth inning just can’t happen,” said Taillon, blaming poor location for Bogaerts’ and Devers’ hits.

Loaisiga did well to keep the Red Sox from adding more runs by striking out Hernandez and getting Vazquez on a popup. In the following frame, Torres’ sacrifice fly, which plated Aaron Judge, made it 3-all. Loaisiga worked out of more trouble in the seventh by getting Bogaerts to line into a 5-4 double play with two on and one out.

But it only delayed the inevitable. The Yankees never threatened again and the Red Sox got the big hit that has eluded their rivals so often this year.