Mark Teixeira struck out with the go-ahead run on third base in the 10th inning Friday night.

As much as Red Sox fans would like, they shouldn't hold that against him. A lot of hitters -- even really, really good ones -- swing and miss at 96 mph, Jonathan Papelbon fastballs. That shouldn't be the ultimate moment to determine Teixeira's ability to play in the furnace that is a New York-Boston get-together.

Jason Bay's moment, on the other hand, should be noted.

It was because of Bay that Teixeira had that moment, with the Red Sox outfielder launching (and, as we have learned with Bay, these sort of things are launched) a two-out, two-run, game-tying home run off of the 'Godfather' of closers, Mariano Rivera, in the ninth inning of what turned out to be a 5-4 Sox win, at Fenway Park.

Besides allowing the Red Sox to author the first scene in the first in the teams' 18-episode soap opera, Bay proved, or at least reiterated, something -- he fits in a Boston uniform.

"Yeah, I think so," said Bay when asked if he was more comfortable in the kind of surroundings thrown the Red Sox and Yankees way Friday night. "I got here and everything was a playoff game, but obviously there are certain series and certain times everything get ramped up. It was a playoff-type atmosphere and having gone through the playoffs it's not something new, it's not something you're getting used to. I've been here before and I've done that.

"I think that no matter where you've played and what you've done there is a certain grace period that you need. I felt a lot more comfortable now. I'm just a little more prepared and there's a little less of the novelty. Now it's just another series and that's the way I can approach it."

At this time last year, Bay was a good player, just as good as he showed Friday night, in fact. He was hitting home runs, and by the middle of June he even had his first walk-off home run. But he was also doing it in Pittsburgh.

There were no Red Sox-Yankees-type series, and certainly no playoffs. Basically, there was no way to tell how Bay would respond to the bright lights and big cities.

But now we do.

First came the production immediately after the trading places with Manny Ramirez, hitting .293 with nine home runs in 49 regular season games. Then, just after warming up under a Jumbotron playing Ramirez's prodigious playoff home run in Chicago, Bay went out in his first post-season go-round and hit a Game 1 home run, which was followed by a .419 batting average to finish off his initial playoff series, against the Angels.

Then came the 92 mph cutter from Rivera.

We all know about how Bay is a free agent at the end of this season, and the fact he will most likely fall into the top tier of available players if he doesn't re-sign with the Sox. That is the future. This is the present, and what we have in the Red Sox' No. 44 is a player who can clearly handle what awaits.

"Youk (Kevin Youkilis, who finished the win with 10th-inning walk-off homer) and I don't have the same demeanor and he does well and he's thrived here. I've only been here for four months so don't put my statue in front (of Fenway) yet," said Bay, who is now hitting .366 against the Yankees as a member of the Red Sox. "It's just being comfortable and people understanding that there are different personalities, where you're not kicking or throwing or whatever it doesn't mean you're not worried about things. I haven't changed since I got here. I'm an even-keel guy. I try not to get too high, or too low."

But Bay's emotional pendulum has swung, and, no matter what the demeanor, that is inevitable at some point (just ask J.D. Drew).

Yet in between those rare displays of emotion, the Canadian with perhaps the driest sense of humor in the clubhouse has what it takes to play here. The ball flying up over the center field wall Friday night just offered the latest confirmation.

"To be honest with you, I've probably fist-pumped and screamed and yelled 20 times more than I ever did," Bay said. "You get caught up in the magnitude of the games, whether it's playoffs or this. You get a lot more animated, which for me is still not that much. But that's when the atmosphere kind of grabs hold of you.

"Everyone told me when I came what it was going to be like. It's a bad analogy, but it's like when people tell you how it is to have kids and you're like, 'I get it', but you have no idea. Everyone is different and you have to go through it. It's like struggling. Everyone needs to struggle at some point to know how to deal with it. I think if you're going to play here, or anywhere else that's a market like this, you need to go through it."