NEW YORK — On game day before his first Yankees-Red Sox game, James Paxton put in a second between-starts phone call to the Boras Corporation sports psychologist that the big lefty has been relying on for advice since he was a Seattle Mariners minor leaguer.

A few simple but important tips were offered:

"Embrace it. Go after it. Be aggressive. Enjoy the intensity.”

After Paxton was 1-2 with a 6.00 ERA in his first three starts since changing teams, disappointing numbers for sure, he felt added urgency to find a quick fix. His club has been in a bind losing games and players, so Paxton thought about all that wisdom Tuesday before heading to Yankee Stadium. He told himself that it was time to prove to himself and everyone else that he was up to the challenge of being a Red Sox killer dressed in Yankees pinstripes.

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Paxton also thought about what he saw on videos from 2017 and 2018 that he watched at home last Sunday night, videos of how he attacked Red Sox hitters successfully when he was pitching for the Mariners.

“I was like, ‘Hey, that looks different,’” Paxton said. “I just thought about it and saw the differences. I decided the delivery that I saw was one that I wanted to repeat. That’s when I’m at my best.”

And so, Paxton made a little mechanical tweak, he soaked in the sports psychologist’s suggestions and it created the hard-throwing stud that the Yankees hoped they were getting when trading two of their best pitching prospects last winter to pry him from Seattle.

Paxton started his Tuesday night with three 1-2-3s and practically cruised his way through a two-hit shutout over eight innings in an 8-0 Yankees win that was a pick-me-up for his slumping club and a punch-to-the-face to the reeling Red Sox, who have followed their 2018 World Series season with a 6-12 start.

The Red Sox had no chance against Paxton, who struck out 12, walked one, hit a batter and still was throwing 99-mph heaters in the eighth inning.

“I find that rhythm and then I feel like I can just go all night,” he said.

Afterward, the quiet and easygoing Paxton admitted being extra fired up for this assignment, and passing this test with flying colors sure felt great.

“This is the definitely the biggest rivalry game I’ve ever pitched in,” he said. “I loved the energy that was going on in the stadium. You could feel it right from the get-go how into it the fans were. That makes it so much more fun for us and so much more fun for me to be a part of.”

His last two sports psychologist’s talks helped, one last Saturday about being more aggressive on the mound and the other on Tuesday.

“I think it was big,” Paxton said. “I felt like those conversations helped. After every start, good or bad, I talk to the guy. I talk to the guy about what happened and how I can do better and what I can keep doing.”

His mechanical fix helped, too. The change, Paxton explained, “was just driving down the mound a little better,” and that allows him to “get that momentum going toward the plate.”

Whatever works.

The Yankees need Paxton to pitch like an ace more than ever with No. 1 starter Luis Severino sidelined at least until the All-Star break, and like his no-hitter last season, this was another sample of how good he can be. Now he needs to rinse and repeat every five days.

Doing this to the Red Sox certainly has him oozing confidence.

“It was a big start to get my feet under me and show myself that I can be here and do this,” Paxton said.

Randy Miller may be reached at rmiller@njadvancemedia.com. Follow him on Twitter @RandyJMiller. Find NJ.com on Facebook