CHIBA, Japan — Athletes cannot build championship careers out of moral victories, so Mariel Zagunis surprised herself Monday afternoon. For nearly two decades, the Olympics had provided her joy and dealt her heartache, emotions that were extreme but also simple. She celebrated or she mourned. She won or she lost.

And then came a solemn walk off the strip at Makuhari Messe Hall B and three steps down a red staircase. The end of her fifth individual Olympic performance had come too soon, in the quarterfinals of the women’s sabre tournament, two victories short of a medal and three shy of her third gold. Zagunis knew she could still win, even after everything she had endured over the past five years, and it hurt that she had not.

There were not many fresh experiences left for Zagunis at the Olympics. She won a stunning gold in 2004 at 19, when she made the team as a last-minute replacement only to land atop the podium. She had dominated as a favorite in 2008, another gold. She had carried the flag at the Opening Ceremonies in 2012. She had won a team bronze in 2016, a fourth medal that made her the most decorated Olympic fencer in American history.

But as she took her first steps out of the strip’s spotlight, Zagunis felt a new sensation. It was something she had earned, no less than she had earned all the medals that filled her trophy case back home in Portland. It was something like perspective.

“I’m actually really proud of the way I fenced,” Zagunis said about an hour after her loss to Russian Sofya Velikaya. “It’s very rare for me to come away from a tournament I haven’t won and actually be happy with my performance. That’s unfortunately what happened today — fortunately and unfortunately.”

Like track star Allyson Felix, who will run later at these Games, Zagunis had reached her fifth Olympics but her first as a mom. In 2017, Zagunis gave birth to her daughter, Sunday. She had to recover from the physical trauma of delivery. She had to return to her training schedule. She had to concentrate on how she ate and slept, aware that most every decision would sacrifice either her fencing ability or her family.

“Oh, my gosh, I feel like an air traffic controller sometimes,” Zagunis said in the lead-up to these Games. “Every decision also impacts this tiny little human you’re trying to protect and cultivate.”

Zagunis proved to herself she would not have to choose between motherhood and elite athleticism. She clinched her spot on the Olympic team by winning the World Cup in March 2020. And then everything changed again. The pandemic meant she would be competing at the Olympics not at age 35, but at age 36. All the carefully calibrated routines she had developed evaporated.

Zagunis persisted. It still felt a little surreal that the Games were happening at all, that she was walking around the Olympic Village, squinting to recognize old acquaintances with masks pulled across their faces.

The past five years may have taken a toll, but on the strip, Zagunis remained a force. In the round of 32, she demolished Canadian Gabriella Page, 15-3. In the round of 16, she pulled away from South Korean Jiyeon Kim, who beat her out of a medal in the semifinals at the 2012 London Olympics, and won, 15-12.

The victory sent her into the quarterfinals against Velikaya, the second seed and a common foe. Velikaya admitted to nerves when she saw Zagunis in the draw.

“She’s an experienced fighter; she’s psychologically strong; she’s unbelievable at dealing with stress,” Velikaya said in Russian.

Zagunis relished the bout for what it represented: Velikaya has two children, born in 2013 and 2018.

“Fencing another mom, having that unspoken understanding of like: We’re here, we’re doing this,” Zagunis said.

Zagunis started fast, winning the first three points in rapid succession, pushing Velikaya back on the strip. Velikaya switched her strategy, mixing up distances. She drew even. The touches snowballed. “In sabre, it goes really quickly,” Zagunis said. “I kind of let it get away from it.” Velikaya won, 15-8.

Zagunis pulled off her mask slowly and took a calm walk off the arena floor. She had fenced well, and after all that happened, she could not bring herself to be angry.

“Just knowing what I’ve been through, what my body’s been through, what we’ve all been through with covid, everything accumulating, the past five years has been a really long and arduous, challenging journey,” Zagunis said. “Lot of ups and downs, lot of things to figure out. I just thought it came together really nicely for me today. Unfortunately, it just didn’t happen.”

Zagunis still has a team competition left, and she has been too focused on Tokyo to make any concrete decision on Paris in 2024. But she made clear she has not ruled out taking a run at her sixth Olympics. The way she fenced and how strong she felt gave her confidence in her physical condition, a crucial factor at her age.

“You know, I really didn’t want it to be over,” Zagunis said. “It was over too soon, because I feel like I have more in the tank. I’ve just put in so much work that I feel in a really good spot physically.”

The Olympics are in Zagunis’s blood: Her parents rowed at the 1976 Games. She does not want her last Games to be defined by empty arenas and spitting into a tube every morning. Each year of training, with its physical toll and international travel to competitions, “makes your brain want to explode,” Zagunis said. Knowing it would take three years, not four, makes sticking around more tempting. And there is also, maybe strongest of all, the desire to win again.

“Having won gold before, I just know that it’s in me,” Zagunis said. “It’s possible.”

There was no gold for Zagunis at these Games, and in the past that is all that would have mattered to her. On Monday, she fenced well, and she was there. After the past five years, that was enough.

“The most important thing is to walk away from this individual competition with my head held high knowing that I’m just really proud to be here and that it can be done,” Zagunis said. “You don’t have to just choose motherhood or being a professional athlete, or motherhood or career. Just setting an example to be proud of yourself for what you can accomplish, even if it doesn’t mean getting everything in the end.”