Speaking through an interpreter, Tazawa said that he was aware of the home run's historical significance.
"I wasn't thinking about that at all," Tazawa said. "I should have used my breaking ball before I got to that point. I have regrets about how I approached that at-bat. But I wasn't thinking about [the milestone]."
With the benefit of hindsight, Tazawa admitted the pitch was a bad idea.
"It was a pitch that I thought could have been a ball, but it caught too much of the plate," Tazawa said. "I knew that he could be aggressive in that kind of situation. I wanted to go in a lot more, but it didn't end up that way."
It was a tough way for the Red Sox to lose.
"Yeah, 3-0 fastball," said Red Sox manager John Farrell. "Challenged him, got beat. Hindsight on that one is going to be 20-20. I think everyone probably realized what he was up there for. Unfortunately, 3-0 pitch found too much of the plate after falling behind in the count."
Catcher Sandy Leon, thrust into the game after Ryan Hanigan suffered a fracture in his right hand, wasn't expecting A-Rod to unload on the 3-0 pitch.
"It was supposed to be fastball inside," said Leon. "I didn't think he was going to swing."
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.