NEW YORK -- Alex Rodriguez raised his right arm as he rounded first base, ready to celebrate his game-winning two-run homer off Seattle closer David Aardsma.

There was just one problem: It was only the eighth inning.

"I honestly thought it was the ninth inning and we walked off. And I was gonna go to the spread and get food," Rodriguez said of his tiebreaking homer with one out in the eighth of the Yanks' 4-2 victory on Thursday. "I thought I hit a much bigger home run than I actually did. I hit it, and I looked at A.J. [Burnett] and [Andy] Pettitte, and they weren't jumping over the railing. At that point, I was like we probably have one half-inning to play. It's pretty embarrassing."

Rodriguez's blast was his fourth in eight games, his 12th of the season and the 595th of his career. He is now just five shy of becoming the seventh player to hit 600 home runs.

"I will embrace it. You look at 600, and it's hard to ignore it because you see it up on the scoreboard, you hear fans talk about it, and you guys ask me about every home run I hit," Rodriguez said. "But 600 is not the end of the season, and it's not the end of my career. I'm going to use it kind of like first base: You want to go right through it and really just use it as a springboard for good things to come."

The home run came just minutes after the Mariners had tied the game in the top of the eighth off CC Sabathia, and it made a winner out of the Yankees' ace for the 10th time this season.

Mark Teixeira had started the rally with a one-out single off Aardsma, the Mariners' closer who was used in the eighth inning of a tie game on the road. Rodriguez then fouled off Aardsma's first-pitch fastball.

"First pitch I swung at, I was a little late," he said. "I just made my adjustment."

On Aardsma's second delivery, a letter-high heater, Rodriguez went the other way with it into the second row in right field.

"Any time I hit the ball to the middle or the other way, that's a good sign," said Rodriguez, who also doubled to center field in the sixth inning. "I am getting healthy, and I'm feeling much better."

Rodriguez's pursuit of 600 homers had slowed to a crawl in June, when he went 19 days between his eighth and ninth home runs of the season. Even with his recent spate of home runs, this is the latest Rodriguez has hit his 12th home run of a season; he also hit his 12th on July 1, 1997.

That said, it's not as if Rodriguez hasn't gone on ferocious tears in the past, and with the way he's swinging the bat now, it may not be long before he reaches another career milestone.

"It's going to be hard to ignore," manager Joe Girardi said. "I didn't have a lot of milestones, so I can't really tell you what he's experiencing. I think it's got to be somewhat in the back of his head. ... but I'm not sure how much it will get in his head once he gets in the box."

Rodriguez himself just hopes it doesn't take as long as it did for him to hit his 500th home run in 2007, when eight games separated No. 499 from No. 500.

Joked Rodriguez, "It took me about two months to get 500, so I don't want to learn too much from that."