SEATTLE -- Yankees rookie Gary Sanchez continued his historic power surge, but the two chances he was denied garnered almost as much attention.

Sanchez homered for the seventh time in eight games and Masahiro Tanaka outdueled former Japanese league teammate Hisashi Iwakuma to lift the New York Yankees to a 5-0 victory over the Seattle Mariners on Wednesday afternoon.

"Well, you feel like he's going to hit the ball hard, is what you feel," Yankees manager Joe Girardi said of Sanchez. "And, you're not sure where it's going to end up, but you feel like he's going to the hit ball real hard. He's been locked in and it's been fun to watch."

Sanchez staked the Yankees to a 1-0 lead with two outs in the first, hammering the first pitch 420 feet into the upper deck in left field for his ninth home run since being called up Aug. 3. He also doubled in the fifth and was walked intentionally in the seventh and ninth with runners aboard and first base open -- both times with Mark Teixeira on deck.

"He's earned it. He did a lot of damage against us. And, it's not just the damage, it's how he's doing it, hitting the ball out of the park," Mariners manager Scott Servais said of the intentional walks. "I certainly respect Mark Teixeira and what he's done in his career -- I've seen a lot of it -- but you're playing the game and watching it with the naked eye, it's pretty obvious who's hot. Sanchez had a heck of a series."

Sanchez -- who had only 10 home runs in 71 games at Triple-A Scranton/Wilkes-Barre this season -- is one of five players in major league history, since 1913, with nine or more home runs in his first 21 career games and one of nine with 15 or more extra base hits in that span.

"I understand it, but the focus is not about me, it's about winning games here," Sanchez said through a translator. "That's where my focus is, go out there, play hard and win some games."

Tanaka (11-4) allowed six hits in seven scoreless innings, striking out five and walking one to improve to 5-0 in five career starts against the Mariners. It was the second time this season that Tanaka has bested Iwakuma.

"I think I was a little bit overthrowing the first couple of innings, but afterward, I was able to adjust that," Tanaka said through a translator. "Also, they were trying to get some contact on the ball, so I just tried to place it in a good location where I could get some ground balls or possibly fly outs."

Tyler Clippard got two outs in the eighth, but allowed two singles. Dellin Betances came on and struck out pinch-hitter Mike Zunino and then finished for his sixth save, giving Joe Girardi his 800th victory as Yankees manager.

Iwakuma (14-9), who had won eight of his 10 previous starts, allowed three runs on six hits in six innings to lose consecutive decisions for the first time since April.

"Kuma was not on," Servais said. "Again, I give him a ton of credit. He figures how to manage through it and you look up, and it's still only 3-0 and you're still thinking you've got a chance."

New York added a run in the second when Aaron Judge was hit by a pitch and Aaron Hicks and Tyler Austin followed with consecutive singles.

With Mariners third baseman Kyle Seager out after fouling a ball off his foot Tuesday night, the Yankees took advantage of Shawn O'Malley, making his first start at third. Hicks singled with one out in the fourth, and Austin then bounced one to O'Malley, who was late on the throw to second, with both runners safe. Ronald Torreyes singled to load the bases and Brett Gardner followed with a sacrifice fly to make it 3-0.

The Yankees, who have won 10 of their last 11 at Safeco Field, increased the lead to 4-0 with a run off Arquimedes Caminero in the seventh. Gardner singled on a high infield chipper and advanced on Didi Gregorius' sacrifice. Sanchez was walked intentionally, but Mark Teixeira followed with an RBI single to left.

Starlin Castro delivered the Yankees' final run with a bases-loaded sacrifice fly in the ninth.

Tanaka worked out of a jam in the second when Adam Lind singled with one out and took third on Leonys Martin's line-drive single off the wall in right. After Martin stole second, Tanaka retired O'Malley on a comebacker and Chris Iannetta on a ground out to short.

After losing the series opener 7-5 on Monday despite two homers apiece from Sanchez and Castro, the Yankees held Seattle to just one run in the final two games to win three consecutive road series for the first time this season.

NOTES: Mariners 3B Kyle Seager was out of the starting lineup after fouling a ball off his foot on Tuesday night. After the game, manager Scott Servais said the injury was a bad bruise and hopeful that Seager would be ready Thursday in Chicago. UTL Shawn O'Malley, who has started at shortstop, second base, center field and left field, made his first start at third base. ... With Wednesday's victory, Joe Girardi became the sixth Yankees manager to reach 800 wins -- the last being Joe Torre. ...With a day game after a night contest, hot-hitting 3B Ronald Torreyes got the nod in place of Chase Headley, Mark Teixeira was the DH instead of Brian McCann, who caught Tuesday night. Aaron Hicks got the center field start in place of Jacob Ellsbury. ... The Mariners list Thursday's starter for the series opener at Chicago against the White Sox as TBA, although Servais said it would be a left-hander. LHP James Paxton, who is on the 15-day disabled list (left elbow contusion) since Aug. 8 after being hit by a line drive, is the likely candidate. Paxton (4-5, 3.53 ERA) pitched three scoreless innings at Triple-A Tacoma on Saturday with no after-effects. ... Yankees RHP Bryan Mitchell, who has been on the disabled list since April 3 (left great toe tear), allowed one run on three hits over four innings in a rehab start Tuesday night with Double-A Trenton. ... Seattle DH Nelson Cruz was pinch-hit for in the eighth inning due to back spasms. Servais said Cruz was feeling better after treatment and he hoped Cruz also would be available in Chicago.