Fiona O’Keeffe had no idea she was about to smash history.

“I was looking at my watch a little bit,” O’Keeffe told NBC Olympics. “But I didn’t really know what pace I was on at all.”

It was just after 11:30 a.m. ET in Orlando, Florida, midway through the 2024 U.S. Olympic Marathon Trials. O’Keeffe was competing in the first professional marathon of her career. 

That’s right — the 25-year-old from Davis, California, was completing her first marathon with an Olympic berth on the line.

“We had taken the last couple of years to just gradually build up the training,” O’Keeffe said. “When the timing was right, we decided to go for my first marathon. It ended up just being that the timing lined up right for the Trials to be my first one.”

So, O’Keeffe entered her first marathon with an Olympic spot at stake.

“There was some level of fear of the unknown,” O’Keeffe said. “But I was really excited to just go run the marathon and see what I could do.”

Meanwhile, O’Keeffe’s coaches — Alistair and Amy Cragg, both former Olympic distance runners — oozed confidence.

“I thought she’d be one of the best marathoners the U.S. has seen,” Amy Cragg remembered. “I’ve been fortunate to be teammates with some of the best marathoners ever, like Deena Kastor and Shalane Flanagan, and I just saw so many pieces of them in her.

“I kept telling her, ‘I think you’re a marathoner. Doing this will feel like coming home. This is your event.”

Wearing a mustard-yellow Puma tank top and a now-viral bloodied bib, O’Keeffe lined up alongside a loaded field, one Cragg called “insanely” tough.

“You still had to have some reservations about it,” Cragg said. “She is so young, and this was her first marathon.”

On a potentially life-altering 70-degree sunny February day in Orlando, she started admirably. After five miles, O’Keeffe was in second place behind Keira D’Amato, a 39-year-old veteran considered one of the favorites to clinch an Olympic slot.

But around the 14-mile mark, O’Keeffe made her move, cruising past D’Amato and into the lead.

“She took the lead earlier than we were anticipating,” Cragg said. “But we also told her, ‘This is your race, and at some point, you have to make an executive decision.’ And so, she made that decision to go.’”

And go she did. At the 20-mile mark, O’Keeffe still led the pack.

As O’Keeffe ran toward a spot on the U.S. Olympic team, Alistair Cragg was dashing madly around the course to follow his pupil's progress. Amy, meanwhile, watched on TV from a nearby hospitality room with their then-four-month-old daughter Isla in tow.

“Fiona looked the best out of everyone,” Amy Cragg said. “I thought, ‘She’s got this.’”

By mile 24, her advantage on fellow Olympic qualifier Emily Sisson had ballooned to 39 seconds, a tremendous gap.

“I had to pinch myself,” O’Keeffe told NBC Sports’ Lewis Johnson.

O’Keeffe’s lead continued to grow as the finish line came into view. At last, 2 hours, 22 minutes and 10 seconds after starting, O’Keeffe crossed the bright red finish line in downtown Orlando with both palms extended to the sky, wearing a big grin on her face.

O’Keeffe had just won the U.S. Trials and qualified for the Olympics in her first marathon, along with Emily Sisson and Dakotah Lindwurm.

O’Keeffe knew these things.

But she had no idea that she’d set a record in the process: the fastest-ever time by a woman at the U.S. Marathon Trials, smashing the mark of 2:25:38 set by Flanagan in 2012 in Houston.

Around the time of her postrace press conference, O’Keeffe caught wind of her record-breaking achievement.

“I was surprised,” O’Keeffe said. “I didn’t think I would run that time. I was just so focused on coming in the top three and making the team.”

O’Keeffe’s next race, incredibly, is the 2024 Paris Olympic Marathon.

Less than a year ago, the path to Paris felt even further from her grasp. O’Keeffe was in Mammoth Lakes, California, in late May, training for the 2023 USATF 10 km Championships when she looked at her left ankle and grimaced.

It was “big and puffy,” and in severe pain. O’Keeffe went to the hospital to have the ankle examined.

“The doctor did an ultrasound to check it out,” O’Keeffe said. “Then, next thing I know, they're telling me that I'm gonna need to stay the night. Then, they're operating on my ankle.”

The exam revealed a staph infection in O’Keeffe’s left ankle, requiring surgery.

“At first I was just like, ‘Are you serious?!’” O’Keeffe remembered. “We had no idea where the infection came from. It was frustrating because this thing randomly happened to me out of nowhere.”

O’Keeffe told herself it’d be no big deal — that she’d be back to running in five days, no problem.

“It ended up being a bit of a bigger deal than I planned for,” she said. “It was a slower road back.”

O’Keeffe’s ankle didn’t have its full range of motion, and the antibiotics had her system out of whack. So, she missed the 10 km championships and spent the rest of the summer rehabbing.

It wasn’t until the end of that summer that she felt semi-normal again.

“That injury is why Alistair and I were holding our breath so much,” Cragg said. “We’d seen her get in shape before, and then something happens.”

But O’Keeffe remained healthy throughout the fall and lined up fully healthy for her chance to become an Olympian.

O’Keeffe is still relatively new to the pro ranks. She joined PUMA as a pro in 2021 after a decorated collegiate career at Stanford University, where she was a six-time NCAA All-American specializing in the 5000m.

She graduated from Stanford with a degree in earth systems, then enrolled as a grad student at the University of New Mexico. There, she studied biology with a focus on ecosystems and climate change.

While studying and running in Albuquerque in December 2020, O’Keeffe qualified for the U.S. Olympic Track and Field Trials in the 10 km.

O’Keeffe then decided to go all in and turn pro.

“I wanted to give it a shot,” she said. “I was enjoying my experience in New Mexico, but I figured I can always come back to school later in life.”

As her career began to develop, O’Keeffe and her coaches realized that she had the makings of a long-distance specialist.

She crushed her first half marathon, finishing fourth at the Aramco Houston Half Marathon in January 2022.

“I said to myself, ‘OK, the longer stuff is clearly my strength and I enjoy it,’” O’Keeffe said. “I started getting a lot of questions about when my first marathon would be.”

That first marathon — her 2:22:10 dash through Orlando’s streets — has since changed her life.

“Everything since has been a total whirlwind in a fun way,” O’Keeffe said. “It definitely has happened much sooner than I expected.”