But with the championship belt that the Yankees pass around to the player of the game resting on his chair and a cluster of reporters quickly gathering to talk to him, Nunez couldn't hide his smile for very long.
"I'm so excited. I'm so happy," Nunez said, his voice expressing the same emotions. "It's the most exciting moment of my life right now."
Regardless of context, a player's first Major League hit stays with him forever. Manager Joe Girardi knew his was on Opening Day off Floyd Youmans, just like Curtis Granderson could rattle off how his came off Freddy Garcia in his hometown of Chicago in a game his team trailed handily.
But when that hit wins your team a game, well, that just amplifies the joy.
Nunez's base hit was the third of four consecutive singles to right for the Yankees in the seventh, leading to three runs, a lead and a bit of a cushion for the bullpen. Austin Kearns started it with a one-out single off Jason Vargas, extending his hitting streak to 10 games, and Granderson lined a single to move Kearns to third and set the stage for Nunez.
"I didn't want to try to do too much. I just wanted to get a pitch and drive the ball," said Nunez, who found a hole between Casey Kotchman and Chone Figgins on a 1-1 fastball to score Kearns and break a 4-4 tie. "I felt like, 'Wow.' You'll remember it all your life."
"He just threw his bat at it and [the ball] squirted through the hole," said Vargas. "When something like that happens, you can't do a whole lot about it."
Derek Jeter followed Nunez with his own single to right off Jamey Wright to score Granderson, and Nunez came around on a Mark Teixeira sacrifice fly.
Nunez's big hit helped soften the news that the man he replaced in the starting lineup on Saturday, Alex Rodriguez, is headed to the disabled list. It also helped improve the Yankees' record without their star to 11-0 this season.
Nunez could be the primary beneficiary of Rodriguez's absence, getting a long look at the hot corner over the next two weeks.
"I'll do what I can do," he said of filling in for a man with 600-plus home runs. "I feel very comfortable there."
The seventh-inning rally came out of the blue against Vargas, who after surrendering four runs in the first had retired 17 of 18 hitters before Kearns' single. The left-hander finished having yielded seven runs on eight hits in 6 1/3 innings -- all seven runs and all but one hit came in either the first or the seventh frames.
The Yankees needed that kind of offensive production with Javier Vazquez again laboring on the hill. Vazquez's third pitch of the afternoon was lined into the seats in right field by Ichiro Suzuki, marking the second straight day that the Yankees' starter allowed a home run before recording an out. Vazquez's 10th pitch of the day, though, went substantially farther. Russell Branyan, fresh off a two-homer game on Friday, launched an 86-mph fastball on a 3-1 count from Vazquez into the fourth deck in right field -- uncharted territory in two seasons at the new Yankee Stadium.
Branyan is also the only player to homer off the glass of the Mohegan Sun Sports Bar in center field at the Stadium.
"There's something about him in this ballpark that he really likes," Granderson said. "Today, for him to hit the ball that far, is absolutely amazing."
Vazquez served up a second homer to Ichiro in the third, and he departed after giving up a leadoff single in the fourth. It was the third straight outing in which Vazquez did not complete five innings; since he tossed seven innings in Cleveland on July 26, each of his five starts has been shorter than the one before.
"His stuff just wasn't crisp today consistently," Girardi said. "At times, he had some good changeups, at times he had good curveballs and good fastballs. But there were other times it wasn't where he wanted to throw it."
Chad Gaudin kept the Yankees in the game, hurling three scoreless innings of relief while limiting the Mariners to just one hit.
"That's the game-winning performance in my mind," said Teixeira. "If Chad doesn't go out there and do the job, we're burning our bullpen and having to come back again from a behind. It would have been a tough day for us."
But the star of this day was Nunez, the 23-year-old who had never been to New York before Thursday. Three days later, the Yankees have a win, largely because Nunez has his first hit, his first RBI, a souvenir baseball he'll give to his mother and a memory he'll never forget.
Tim Britton is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.