"That was the beginning," Pierce said at the Brooklyn Nets' shootaround Tuesday morning. "It lets you get a taste of it, you enjoy those moments. I just grew and it manifested over the years, to where you love those moments."
The 36-year-old put on a late-game display in the Nets' 94-87 victory over the Toronto Raptors in Game 1 of their best-of-seven playoff series.
Pierce scored nine points in the final three minutes to grab the game by the throat. He wasn't particularly great to that point, but he scored when his team needed him most. That's what he does best.
Asked where his ability to perform under pressure comes from, the player known as "The Truth" grinned.
"I think it's just in the DNA," he said. "Everybody don't have it, everybody's not born with it. Can't buy it at Costco or Walgreens. It's in the DNA."
Asked how he's sustained his intensity, the perennial all-star and 16-year NBA veteran replied: "Like I said, it's in the DNA. There's nothing I can do to let it go, I can't lose it, I can't break it. It's in there, it's in there."
The Raptors were set to face the Nets in Game 2 on Tuesday before the series shifts to Brooklyn for Game 3 on Friday.
Pierce, a member of the 2008 NBA champion Celtics, was acquired along with Kevin Garnett by the Nets in a 2013 blockbuster trade Boston.
Pierce looked completely unfazed by the noisy soldout crowd at the Air Canada Centre on Sunday, and in fact looked like he was enjoying it. He said afterwards that a win on the road is often more satisfying than a victory in the friendly confines of home.
"A lot of players shy away from the moment, some (welcome) it, Paul's one of them," Garnett said. "Paul looks to see himself in a different light and he comes out and plays like it. I've seen him do it countless times, I've seen him look for the moment. . . He wants it, he takes it over."
Pierce had some fun when he walked off the court Saturday, tossing his headband up into the crowd. Twice the headband was thrown back at the grinning Nets star before a fan eventually kept it.
Nets coach Jason Kidd, who knew Pierce well from playing against him, said the Nets star loves the big stage.
"He enjoys the moment," Kidd said. "He's as good as they come. Playing against Paul, understanding that he's a competitor as an opponent, but now seeing him up close on a daily basis, he's a true professional. For the young guys in the league, he's a prime example of what it means to be a pro."
While much has been made of the disparity between experience of the two teams in this series, Pierce said there's definitely something to that.
"Not getting rattled, staying focused through may be bad calls going against you, staying focused even though the crowd is going crazy, as a young team or a team less experienced, sometimes you can get rattled in those situations," Pierce said.
"A lot of us have that experience to now that when these times come, you know what to do."