SEATTLE – The trademark that accelerated Masahiro Tanaka's path to the Majors was his ownership of a devastating splitter, one that prompted batters across the globe to flail or make weak contact. As he continues to reinvent his arsenal, the slider has developed into a pitch worthy of attention on its own.

That was the case on Tuesday night, as Tanaka hurled seven masterful scoreless innings in the Yankees' 7-0 victory over the Mariners at T-Mobile Park. Tanaka leaned on the slider more than any other grip, mixing it with his fastball and the splitter to create a dominant three-pitch mix.

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"I think I had pretty good command on it. That was working for me today," Tanaka said through a translator. "I'm not sure if it actually became better, but I felt my slider has always been pretty consistent going back to last year."

Supported early by Aaron Judge's 100th career home run, Tanaka outdueled Yusei Kikuchi in a matchup of Japanese starters. Kikuchi and Tanaka had conversed prior to Monday's series opener, when Kikuchi – 2 1/2 years Tanaka's junior – reflected about witnessing Tanaka's success as a high schooler in the Koshien tournament.

The words were appreciated, but that feels like a lifetime ago to Tanaka, whose attention is focused on the present as he navigates his sixth season with the Yankees. Bouncing back from a troubled start against the Athletics, Tanaka improved to 8-0 in 10 career starts against the Mariners, scattering three hits in a 106-pitch effort.

"That was huge. That was a big performance," Judge said. "He attacked guys and even when he got behind, he was able to work that slider in there, that splitter, and get back in the count. When he's able to do that, he's dangerous."

Of those pitches, 42 were sliders, generating eight swinging strikes, 12 called strikes and seven foul balls. Yankees manager Aaron Boone raved about Tanaka's increasing confidence in the slider.

"There have been a number of starts, especially at the start of the year, where that split was inconsistent for him," Boone said. "That was the secondary he had to lean on. He was forced to be really strong with it. I think it’s been a pitch that has continued to improve for him."

Tanaka held Seattle hitless until the fifth inning, when Kyle Seager opened the frame with a double to right field, then Tanaka kept the shutout going in a one-walk, seven-strikeout gem. His 1.89 lifetime ERA against the Mariners is his lowest against any club that he has made at least three starts against.

"He doesn’t throw many fastballs for strikes," Mariners manager Scott Servais said. “With young hitters and an aggressive team like we are, you get into those fastball counts and he has the ability to take a little off and go to the slider or split-finger. He’s got a ton of experience and he knows how to pitch.”

While Kikuchi had been amped for the start, having referred to Tanaka as one of his baseball idols, Judge hung a pair of runs on the rookie lefty almost instantly. With DJ LeMahieu aboard, Judge mashed a 462-foot rocket off the batter's eye in dead center field for a two-run homer.

Judge's 100th homer came in his 371st career game. Only Ryan Howard (325 games) and the Yanks’ Gary Sanchez (355 games) did it faster. Brett Gardner added a three-run homer in the third inning off Kikuchi, who was charged with five runs and eight hits over four innings.

"First and foremost, getting some early runs from our offense, I think that helped," Tanaka said.

Tanaka's strong effort placed the Yankees in position to notch a winning road trip if they complete a sweep of the Mariners on Wednesday, and that would have appeared to be a long shot following the three-game sweep in Oakland last week.

New York rebounded with two wins in three games against the Dodgers in Los Angeles, a series that might have ended with a Yankees sweep if not for a late, controversial call in the middle game of the set. Nevertheless, the ideal formula of strong pitching and big blasts worked to perfection in this one.

"When we haven’t played well in short stretches, we’ve done a good job of turning the page, getting things going in the right direction," Gardner said. "That all kind of starts with Masahiro and what he did tonight. It's really fun to watch him pitch."