The Yankees' Aaron Judge, right, celebrates with Kyle Higashioka as...

The Yankees' Aaron Judge, right, celebrates with Kyle Higashioka as he returns to the dugout after hitting a grand slam off Pirates relief pitcher Manny Banuelos during the eighth inning of a game in Pittsburgh on Wednesday. Credit: AP/Gene J. Puskar

PITTSBURGH  – Among the more impressive numbers the Yankees have put up the first half of the season is  that they’ve lost three in a row just one time.

Luis Severino, backed by homers from Josh Donaldson, Joey Gallo, Kyle Higashioka, Aaron Judge – who hit a grand slam off former teammate Manny Banuelos in the eighth – Aaron Hicks – who hit a ninth-inning grand slam off infielder Josh VanMeter – and Giancarlo Stanton, kept that number at one Wednesday night as the Yankees crushed the Pirates, 16-0, in front of a crowd of 32,414 at PNC Park.

“A lot of good at-bats,” Aaron Boone said. “They broke out in a big way. Good to see everyone kind of get involved.”

The Yankees (59-23), who had a season-high 22 hits, start a four-game series against the resurgent Red Sox Thursday night at Fenway Park. They bumped their record to 3-3 on this four-city, 10-game trip that started last Thursday in Houston.

Speaking of impressive numbers, Judge’s grand slam gave him 30 homers just past the halfway point of the season.

“I’ve never seen anything like it,” said shortstop Isiah Kiner-Falefa, who had four hits. “It’s unbelievable.”

Said Judge of No. 30: “I’m glad it came in a win. That’s what’s more important here is this team’s been rolling. We have a good lead in the East and we have big opponent coming up here with Boston.”

The Yankees take a 14-game lead over the Red Sox and Rays into Thursday night.

Severino, 0-2 with a 5.29 ERA in his previous three starts, improved to 5-3, 3.11 after allowing four hits and striking out three over six scoreless innings.

After a 1 hour, 9-minute rain delay, the Pirates first two batters reached against Severino, who then retired 12 straight and 16 of the next 17 batters.

Among the Yankees key hits early were a two-run single by DJ LeMahieu in the fifth inning for the first runs of the game, and back-to-back homers by Donaldson (No. 7) and Gallo – the latter was in a 1-for-33 skid at the time of his 10th homer – in the sixth to make it 4-0.

Higashioka, hitting .164 coming in, added his fifth homer leading off the seventh for a 5-0 lead. Judge’s grand slam off Banuelos, dealt to the Pirates last Sunday for cash considerations after the Yankees DFA’d him June 28, was his third hit of the night and made it 9-0. Donaldson’s sacrifice fly later in the inning made it 10-0. Hicks’ grand slam and Stanton’s blast off VanMeter made it 15-0 and Higashioka’s run-scoring single pushed it to 16-0.

Pirates righthander Mitch Keller came in 2-5 with a 5.14 ERA and pitched to those numbers, allowing four runs and 10 hits, including the Donaldson and Gallo homers, over six innings.

Keller did frustrate the Yankees through the first four innings.  

Matt Carpenter, 14-for-41 (.341) with eight homers, 18 RBIs and four walks in 12 previous starts, started in rightfield and roped a double into the rightfield corner with two outs in the first, but was stranded when Stanton grounded out to end the inning.

Six pitches into the bottom half Severino was in trouble after leadoff man Ke'Bryan Hayes, the son of former Yankee Charlie Hayes, singled and Bryan Reynolds doubled. But Severino started his string of 12 straight retired and cruised the rest of his outing.

Gallo worked a leadoff walk in the fifth and Kiner-Falefa singled to left. Higashioka struck out looking and, as he did, Kiner-Falefa stole his team-leading 13th base. LeMahieu followed and, with the infield in, scorched a fastball back up the middle, the two-run single making it 2-0. Judge hit a towering double off the wall in center but LeMahieu, on a reasonably aggressive send by third-base coach Luis Rojas, was thrown out at the plate to keep it 2-0.

No matter.

There was more to come. Much more.

“Games like this help guys get rolling,” Judge said. “You have a couple of good at-bats, hit a couple balls in the gap, and all of a sudden guys just take off for a week or two or for a whole month or even the rest of the season.”

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