Three games into his second season at the University of Michigan and Tom Brady finally got onto the field. It was late in the Wolverines' blowout victory over UCLA, but the chance to play, the chance to show what he could do after all the waiting and all the practice was coveted nonetheless.

So Brady took the snap, dropped back and heaved a ball to the left. It went directly into the hands of Phillip Ward, a UCLA linebacker, who promptly raced 45 yards the other way for a touchdown.

Tom Brady’s first college pass was a pick-six.

“Horrified,” Brady would say years later.

The rest of the season wasn’t much better. He’d appear in just one other game that season. He’d complete just three passes for 26 yards. He was so buried on the depth chart, he had little hope of seeing the field the next season as a redshirt sophomore, or perhaps even the year after that.

Worse, both the head coach (Gary Moeller) and assistant coach (Kit Cartwright) who recruited him were no longer with the program. He felt like no one believed in him. He felt like everyone questioned him. Transferring, perhaps to somewhere closer to his home in San Mateo, California, felt like the best decision. He went and told head coach Lloyd Carr he was leaving.

Carr wasn’t a yeller or a screamer. He listened, nodded and said he’d grant the release, but on one condition. He wanted Brady to think it over for one night and remember one thing while he did.

“It’ll be something you’ll regret for the rest of your life,” Carr said. “You came here to be the best. You came here because of the great competition. If you walk away now, you’ll always wish you had stayed … you’ll always wonder what would have happened if you stayed.”

The next day Tom Brady, the three-completion, third-string quarterback, walked back into Carr’s office.

“I’m staying,” Brady said, “And I’m going to prove to you I am a great quarterback.”

You can’t boil a career like Tom Brady’s into a single moment. It is too big and too grand and too successful. Too many touchdowns. Too many comebacks. Too many victories.

Brady will finally retire, after 23 seasons, 383 games and seven Super Bowl titles. It is a run so impossibly rich that the twists and turns, ups and downs are almost incalculable. They’ll be writing books about Tom Brady for the next century.

That day in Ann Arbor though was a spark that built a legendary player. It was the start of an unheralded underdog taking perceived disrespect and fueling it to become the ultimate winner.

Today, upon his retirement, Brady is famous and rich and celebrated, but he got there by grinding through doubts, roadblocks and slights, often real, occasionally manufactured. The numbers pop out and any of them could define him — 102,614 yards passing, 737 touchdowns touchdowns, 58 game-winning drives.

Those don’t come without these — seventh on the depth chart at Michigan, fourth at New England, 199th draft pick overall.

Brady would, indeed, prove to Carr he was a great quarterback. It wasn’t easy. He’d sit again as a redshirt sophomore. Even as a junior and senior he’d have to fend off a local star recruit, Drew Henson, and occasional boos from Michigan fans to become the full-time starter. In the end, he had a brilliant final season, including victories over Penn State, Ohio State and Alabama.

The NFL was unconvinced, of course. Brady would wallow in the draft until the sixth round. As the picks rolled on without his name called, an emotional Brady took long walks or stood in his yard taking frustrated cuts with a baseball bat. He pledged to make everyone pay.

New England finally called, though, and by his second season he led the Patriots to the Super Bowl title courtesy of an ice-water game-winning drive to defeat heavily favored St. Louis. He’d go on to win five more titles for New England, post a 16-0 regular season and rack up records upon records. Two years ago, he left for Tampa Bay and captured another Lombardi Trophy, this time without Bill Belichick as his partner, and forever cementing his greatness.

He shed the label of game manager and became a superstar. He outlasted his peers and beat players two decades his junior. No comeback was too big; he once won a Super Bowl trailing 28-3 and in his second-to-last playoff game, he led the Bucs back from 27-3 before they gave up a last-second field goal.

That was Brady. Never give up. Never quit. Never stop looking for challenges.

Brady can leave the NFL knowing the league never got him — he started his final 125 games (holding the current iron man streak among active quarterbacks) and hadn’t missed a game due to injury since 2009.

All of it stems back to proving something to Lloyd Carr, to his Michigan teammates, to himself. All of it came from an internal fire that was bigger than his physical talent. Brady was obsessed with his critics.

He participated in multiple documentaries and projects about being passed over in the 2000 draft. He named his media company "199 Productions." He lived within the constraints of a strict diet and intense exercise regimen to prove he could play and play and play … almost forever.

By the end the upstart was the immovable object. David had morphed into Goliath. The rest of the league bent to his will.

Critics? Doubts? There were none left.

Brady had defeated them all. If quitting, if transferring, if finding an easier, clearer path once appealed to him as a 20-year-old in Ann Arbor, an old coach set him back to reality and onto a path of always fighting for himself.

“You will regret it,” Lloyd Carr told Tom Brady back then.

All these years later, there are no regrets.