CARY, N.C. — Relentless. If there were ever a word to describe the career of Heather O’Reilly, that would be it. Relentless as a winger working up and down the flank. Relentless in her uncompromising approach to training, day after day after day. And relentless in her pursuit of winning and getting the most out of herself and her teammates, whether it was the U.S. national team or clubs on both sides of the Atlantic or her early days at the University of North Carolina.

Hell, even I got to see it up close as O’Reilly’s teammate covering the World Cup for Fox Sports TV last summer. Throughout that tournament, she stayed sharp by working out with a personal trainer, knowing that she would need to be ready for action the moment she rejoined the North Carolina Courage in her final season as a player.

You never know what might happen, and O’Reilly was pressed into starting duty—at right back, of all places—when teammate Merritt Mathias went down with an injury late in the season. Just as she had shown her versatility by moving from forward to winger and extending her national team career back in the day, O’Reilly learned the right back position quickly. She scored a go-ahead penalty late in the NWSL semifinals against Reign FC, and in Sunday’s final O’Reilly helped shut down Chicago winger Yuki Nagasato as the Courage pummeled the Red Stars 4-0 in front of a sold-out home crowd of 10,227 at WakeMed Soccer Park to win their second straight league title.

Karl B DeBlaker/AP/Shutterstock

On the same field where she scored her first national team goal in 2002, the 34-year-old O’Reilly finished her career with yet another trophy. When she came off for a sub late in the game, O’Reilly was surrounded by her teammates, applauded by the Red Stars and given a standing ovation by an adoring crowd that had seen her go through the stages of her career before their eyes.

“It was special,” O’Reilly said afterward. “I’ll remember doing angels in the confetti on the field and looking up at the sky. I’ll remember the locker room scene and a lot of Budweiser. I’ll remember seeing my mom and dad in the stands and my husband, the packed house and the victory lap.”

O’Reilly’s relentlessness was the perfect fit for a North Carolina team that knows only one speed: Full-throttle action on every square inch of the field. On Sunday, that was personified by forward Lynn Williams racing 60 yards downfield in the 19th minute to dispossess Chicago star Sam Kerr. But you saw it in so many other ways, too. Debinha, the Brazilian maestra and final MVP, pushed in the first goal just four minutes after the opening whistle on the Courage’s first break of the game. Forward Jessica McDonald, who leads North Carolina’s suffocating defensive press with Williams, found the end of a Williams cross to make it 2-0.

And Crystal Dunn, the definition of a high-motor player, showed unyielding will to put North Carolina up 3-0 just before halftime. Relentless is one of the names that Jeff Bezos first considered for what eventually became Amazon—Relentless.com actually takes you to the Amazon site—but the Courage have used their own relentlessness to dominate the NWSL in a similar fashion. When the 6-foot tower of power, Sam Mewis, herself an Amazon, headed home in the second half to make it 4-0, the carnage was complete.

Here in American soccer leagues, whether it’s the NWSL or MLS, the organizers try to create parity by instituting strict salary caps. But these are still humans playing soccer, and humans will always aspire for dominance, which is what coach Paul Riley has achieved with his team in recent years. North Carolina has had the NWSL’s best regular season record in each of the past three seasons, and it has now won three of the last four NWSL championships if we include the 2016 title won by Riley’s Western New York Flash, which relocated to North Carolina with many of the same players.

“The core group is still here that started in Western New York,” Riley said after Sunday’s game. “They have just developed really well.”

What they have is quality—almost all of the Courage’s starters are full internationals—and an identity that makes them extremely difficult to play against. On a humid day in the Piedmont, several Chicago players were nearly doubled over from exhaustion, and it was still in the first half.

Karl B DeBlaker/AP/Shutterstock

The Carolina players didn’t care. No Courage player has better embodied her team’s steel than O’Reilly, who now moves on to her full-time job as an assistant coach at the University of North Carolina to her college mentor, Anson Dorrance, as well as a media career if she wants it.

“It’s a lot emotionally to kind of turn that chapter,” O’Reilly said on Sunday night. “I’ve wrestled with it the last couple of months, because I’ve been doing this a long time. But there are a lot of good things ahead of me. Tomorrow’s a new day. We have Carolina practice.”

And with that, an era had ended.