NEW YORK — During their historic nine-game losing streak, one of the Yankees’ fatal flaws was an inability to score first, at one point going 61 consecutive innings without a lead.

Aaron Judge changed that on Wednesday night, blasting a solo homer in his first plate appearance en route to his first career three-homer game. Less than 24 hours later, he did it again, staking the Yanks to a lead in the opening frame of Thursday afternoon’s all-important rubber match.

It wouldn’t hold up, however, as reliever Tommy Kahnle gave up back-to-back homers to Alex Call and CJ Abrams in a four-run seventh inning, sinking the Yankees (61-66) to a 6-5 loss to the Nationals (59-69) at Yankee Stadium. New York has not won a series since it swept the Royals — the second-worst team in the American League — from July 21-23.

Kahnle, who also allowed a go-ahead homer to Abrams in the eighth inning of the club’s 2-1 loss in Tuesday’s series opener, came into the contest after Jhony Brito allowed just the Nats’ second hit of the game to lead off the frame. Until that point, opener Michael King and relievers Keynan Middleton and Brito had allowed only one unearned run.

The Yankees attempted to mount a comeback of their own in the eighth inning, with Giancarlo Stanton blasting a leadoff homer to narrow the deficit to one. Two strikeouts later, No. 3 prospect Everson Pereira — who was called up before Tuesday’s game — smacked a double to the left-field corner for the first hit of his Major League career.

But pinch-hitter Jake Bauers was unable to drive him in, striking out in an eight-pitch at-bat against Washington right-hander Kyle Finnegan.

After the Nats added an insurance run in the top of the ninth, the Yanks again threatened in the bottom half. Stanton cut the deficit back to one with an RBI single, but Harrison Bader flied out to the warning track to strand a pair of runners.