From a warm welcome during pregame introductions to a standing ovation during his first at-bat in the second inning to a sliding grab to end the fifth inning to his 12th-inning heroics, the new everyday Red Sox left fielder had a debut neither he nor the 37,832 on hand at Fenway Park will soon forget.
"The ovation was a little unexpected, especially the pregame announcement, and then at the plate, I wasn't quite sure what I was supposed to do with that," Bay said. "It was very flattering. I hadn't even played an inning yet and to get that ovation was a pretty nice little welcome."
"I think he had a pretty good heartbeat going anyway," Red Sox skipper Terry Francona added. "This place continues to amaze me, the way they welcomed him, the way the fans welcomed him. I don't want to say you never see that because you always see it here. That's pretty special."
Bay thought he might have had the perfect ending to his night before the drive to left-center off A's lefty reliever Alan Embree landed high off the Green Monster in the 12th.
"On the triple, just the last inning, it was just two outs and I was trying to get on," Bay said. "[A home run] was the last thing on my mind, and it turned out to be in a good spot. If it was a double, we might still be out there."
It was Jed Lowrie who drove home Bay with the game-winning run when he beat out an infield single to short.
"We all kind of jumped up on the top step, and that's one of those ones, where if it's in another park, it's probably an out, but he'll learn about the Monster pretty quick," Lowrie said of Bay's near-miss.
On Thursday, like everyone else watching the Trade Deadline, a sleep-deprived Bay wondered where he might wind up.
"Sleepless -- but for good reasons," Bay said on Friday when asked about his previous 24 hours. "[It's] just kind of a whirlwind. [I] actually found out just as probably everyone else did a few minutes or half-hour after the 4 o'clock [p.m. ET] Deadline. We were about ready to get on a bus and go to the airport and head to Chicago, and they called me back and told me, 'You've been traded, you're going to Boston and good luck -- win a ring.' It was pretty exciting."
Bay couldn't help but hear all the rumors involving Tampa Bay, Toronto and Boston.
"My head was spinning," Bay said. "My name was everywhere and ultimately, the Deadline passed and it was like, 'All that and then nothing.' Then a half-hour after the Deadline, they called and told me I had been traded."
Once in Boston early Friday afternoon, he was greeted warmly.
"I had numerous people try to help me with my bags at the airport that I didn't know," Bay said. "It was very, very overwhelming, really. It's going to be something I'll probably never forget, that's for sure. I can't wait. Everyone says the best fans in baseball are here and I can't wait to be a part of that."
That's not to say he doesn't have fond memories of Pittsburgh, where he's played since a midseason trade in 2003.
"It's tough to be removed from what I had known for the last four or five years, pack a bag, get on the flight, get here, meet the entire team, an entire staff, play a game and be submersed in the middle of a pennant race and have a chance to win a ring. I don't think it's going to resonate that quick. I think I'll need a day or two for me to let it sink in, but I fully intend for it to sink in."
A couple of things he may not have had time to pack came from his childhood in British Columbia, Canada, where his father, Dave Bay, was a huge Red Sox fan.
"For whatever reason, my dad was a diehard Red Sox fan," Bay said. "I had a onesie when I was however old, and it was a Red Sox onesie and I still have it. I grew up my entire life with two big posters -- one of Jim Rice and the other of Carl Yastrzemski with the 'New England -- I Love You' saying under it. They are still in my parents' basement."
He won't be trying to fill the shoes of another great Red Sox left fielder named Manny Ramirez.
"I'm not coming in trying to replace anybody," Bay said. "They needed a left fielder. I'm going to play left field, and I can't wait."
"He's going to be our left fielder and he's right-handed and he's going to hit in the middle of our order, but he doesn't have to be Manny's replacement," added Red Sox general manager Theo Epstein. "I don't think that's fair to put on any player. We're not asking him to fill those shoes specifically. We're asking him to be a contributing member to a winning baseball team, emphasis on the last word."
When his No. 44 was flashed on the Fenway Park video board during players introductions, Bay received a 30-second ovation from the crowd.
"Eric Davis was a childhood idol of mine," Bay said of the number formerly worn by Brandon Moss. "He wore 44, so why not."
Bay doesn't take being traded as any sort of insult.
"There's nothing I can do about it," Bay said. "I'd been traded three times in the Minor Leagues before I got to Pittsburgh, albeit that's not the grand scale of this trade. But I felt like I had been equipped somewhat to handle that. I didn't know anything more than what everyone was writing. I was following it just like everyone else was."
Now Bay can get used to playing in Boston while trying to help his new team make a pennant-stretch run.
"If I was a free agent, I couldn't have picked a better place to go to," Bay said. "From what everyone says about Boston and having played here a couple of years ago in Interleague, the atmosphere and obviously the winning, I couldn't have hand-picked a better place."
Mike Petraglia is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.