Not surprisingly, Tom Brady’s time in the N.F.L. spotlight had an almost fairy-tale, prescient beginning. In a Super Bowl that is now 20 years past, Brady’s New England Patriots were two-touchdown underdogs to the St. Louis Rams largely because Brady was a discarded apprentice thrust into a starting role when the marquee quarterback was injured.

But then Bill Belichick conjured a stout defensive strategy and Brady’s competent play kept New England in a tied game until the final 97 seconds, when the Patriots took possession of the football on their own 17-yard line. They had no timeouts remaining.

John Madden, a Pro Football Hall of Fame coach and the most respected broadcaster in the land, begged Brady to run out the clock so the Patriots could await their fate in overtime. “You don’t want to do anything stupid,” Madden, who died in late December, told his many millions of viewers.

A football legend was warning the football nobody. Brady did not listen. He completed three passes and the Patriots moved into Rams territory.

“This guy is really cool,” Madden said, foreshadowing two decades of Brady as a pitchman for everything from Tag Heuer watches to Aston Martin sports cars.

Brady next fired another perfect pass for 23 yards.

“Amazing,” Madden, now a believer, gushed. “They are letting it all hang out.”

After another Brady completion, a 48-yard field goal on the game’s final play gave the Patriots their first Super Bowl victory.

“What Tom Brady just did gives me goose bumps,” Madden said.

In a postgame interview, Brady’s face was flushed, his hair tousled like a child coming in from the playground. He was informed that Madden, before the game’s final drive, had insisted that the Patriots should be playing conservatively, settling for overtime.

“Madden was worried you’d do something stupid,” a reporter said.

Brady, then 24, looked wounded at first. Then he considered what he’d just done.

Smiling impishly, Brady said Madden, the game’s biggest celebrity at the time, was wrong. Brady added: “I can say that, right?”

He could at that moment, and for the next two decades, he could say almost anything he wanted. Brady’s stardom and his football wizardry became profoundly entwined with the narrative of the cultural monolith that the N.F.L. would become over his career.