Last week, Katie Ledecky hosted Thanksgiving dinner at her new house in Gainesville, Fla., surrounded by family members and stacks of moving boxes that would need to be dealt with eventually. After a cross-country move and a month of living out of a hotel, the 10-time Olympic medalist finally was starting to feel settled in, both in and out of the pool.

This has been a season of change for Ledecky, 24: a new team (Gator Swim Club), a new coach (the University of Florida’s Anthony Nesty), a new gig as a volunteer coaching assistant for the school’s collegiate teams and a new set of teammates and training partners — including some of the fastest male distance and middle-distance freestylers in the world.

When she climbed the starting blocks at the U.S. Open in Greensboro, N.C., on Wednesday night — her first official competition since her move from Stanford to Florida two months earlier — Ledecky sported a new swim cap (with “Gators” in trademarked orange script on one side and the Stars and Stripes on the other) and a stroke that she described as more efficient and stripped of “bad habits.”

The result was an impressive victory in the women’s 800-meter freestyle in a meet-record time of 8 minutes 12.81 seconds, 11 seconds ahead of Leah Smith, a two-time Olympic medalist. Though the time was just the 18th fastest of Ledecky’s career — which also made it the 18th fastest by any female swimmer in history (she owns the top 24 in her signature event) — it felt somewhat like a statement swim for the greatest female freestyler in history.

No one, including Ledecky, had posted such a fast time in the 800 free at this point in the calendar. Her 8:12.81 was less than a quarter-second off her gold medal-winning time in Tokyo (8:12.57) on July 31 and more than four seconds faster than where she was at this point on the calendar a year ago (an 8:16.90 at the Stanford Invitational).

“I came into the meet not wanting to focus too much on time, but with the way I’ve been training, I felt I had a couple of good times in me,” Ledecky said in a telephone interview Wednesday night. “It’s a good time. I felt like that was pretty indicative of how training’s been going. But more than the time, I just felt good in the water and felt like I swam a good race.”

Ledecky’s move to Gainesville in late September came less than two months after a four-medal performance in Tokyo that was dazzling by every measure except her own historic standards. Though she won gold medals in the 800 and 1,500 freestyles — the sixth and seventh gold of her Olympic career — she was outtouched for gold by Australian rival Ariarne Titmus in the 400 and failed to make the podium in the 200, a race in which she had won gold in Rio de Janeiro in 2016.

At the time of the move, Ledecky pointed to geography — Gainesville is closer than Palo Alto, Calif., to her family’s home in Bethesda, Md. — and the “opportunity for growth” inherent in any major change as the reasons behind it.

On Wednesday night, Ledecky said little about the technical tweaks to her stroke since she joined Nesty, saying, “I think over the last two months I’ve gotten rid of some bad habits that I formed over the past couple of years — just some small things, like how I’m kicking off the walls, and my stroke just getting a little more efficient.”

The bigger change for Ledecky in the pool is training on a daily basis against a deep and talented group of male distance swimmers led by Bobby Finke, who matched Ledecky with gold medals in the 800 and 1,500 in Tokyo. (Finke, 22, won the men’s 800 in Greensboro on Wednesday night in 7:54.07.) On any given day at practice, Ledecky might line up in the lane next to Finke or Kieran Smith, bronze medalist in Tokyo in the 400 free, and try to match the men lap for lap.

“I don’t always have to be watching the clock during practice” for feedback, she said. “I just try to race the people next to me. We push each other to go faster, and it creates a really great environment.”

Still to come this week for Ledecky in Greensboro: the 400, 200 and 1,500 free — her typical program. She and Nesty have yet to map out a specific schedule for the first part of 2022, but the aim will be to peak for the U.S. trials in April in Greensboro and world championships in May in Fukuoka, Japan, where she will be seeking to add to her career haul of 18 medals (15 golds). Beyond that, in the distance, is the Paris 2024 Olympics.

Wednesday night’s 800 free was just one swim, but in posting a summer-caliber time in the deep of autumn, Ledecky served notice that, at least when it comes to the longest distances, she’s still on top of the sport until proved otherwise.