Hunter Bell finished fourth at the world indoors in Glasgow last year and at the European championships in Apeldoorn earlier this month, but set a new personal best on Sunday to win bronze in three minutes 59.84 seconds.
Ethiopia's Gudaf Tsegay, the world indoor champion in Belgrade in 2022, set a blistering pace to lead from gun to tape and stormed over the line to win gold in a new championship record of 3:54.86.
Tsegay's time was just shy of her own world record set in 2021, and was four and a half seconds clear of teammate Diribe Welteji who took silver ahead of the on-rushing Hunter Bell on 3:59.30.
"Straight away they were running fast so I knew that would suite me to be honest," Hunter Bell told Flashscore. "I knew they would drop off, maybe not Tsegay but the rest of the field. I wasn't looking at the clock but just feeling a good rhythm and wound them back in."
Hunter Bell memorably won bronze on her Olympic debut at Paris 2024 just three years after leaving her job in cyber security, but after a stunning breakthrough year she suffered an ear infection in Apeldoorn and dramatically fell out of contention on the final lap.
"Apeldoorn was the toughest loss of my career so far," she said. "I really went in thinking I could win, so to come fourth I was absolutely devastated.. but I think the mark of being a good athlete is when it goes wrong, learning from it and coming back."
In the men's 1500m, Norway's Jakob Ingebrigtsen became the first man since Ethiopia's Haile Gebrselassie in 1999 to win the middle distance double at the world indoors with a scorching victory.
After winning gold in the 3000m on Saturday, the reigning 1500m world record holder sparkled on his return to the Nanjing Cube in his favoured event to hold off Great Britain's Neil Gourley and cross in a time of three minutes 38.79 seconds.
"Of course this is something special," said Ingebrigtsen. "A lot of things have changed and I'm not doing this because anyone else has done it before. So that's purely a coincidence.
"It's very difficult to compare yourself against history and what others are doing."
Gourley won silver in a time of 3:39.07 for his first world indoor medal, and Britain's first in the discipline for 32 years, finishing ten hundredths of a second ahead of USA's Luke Houser.
"It's brilliant," Gourley said. "This time last year I watched the world indoors as I was injured, really injured, and could barely walk at this point. So I was thinking about that and how I managed to make the line-up today.
"Everything else was a bonus and I went in with that mentality, anything is possible today. It feels really good."
Gourley decided to sit with Ingebrigtsen at the back of the nine-man field from the off but gradually weaved his way through the pack, running shoulder-to-shoulder with Spain's Mariano Garcia before Portugal's Isaac Nader muscled in.
Ingebrigtsen fired a devastating kick around the final 100m as Gourley took the inside line, but he could not catch the Norwegian - unlike Jake Wightman in 2022 and Josh Kerr in 2023 - as he surged over for victory.
"The plan was to hang back and kind of key off what Jakob was doing," Gourley explained to Flashscore. "I knew he'd be at the back and then move around, so it was a case of look, it's not worked for me in the past being towards the front, so the idea was use his momentum when he moves. And that's what I did.
"I thought it put me in quite a good position there to strike - with two laps to go, one lap to go. I just didn't climb to top gear to live with Jakob in the final 100 meters.
"It's huge (to win a world medal). It's validating, considering all the work I've put in to get to that point. I'm not far away in terms of who the top guy was today, so that's the kind of level we're looking at."
However there was disappointment in the shot put for Great Britain with Scott Lincoln exiting the competition in the first round with a throw of 19.88m.
Lincoln finished 18th at the world championships in Budapest in 2023 and 21st at the Olympic Games in Paris 2024 and lamented another "bad day in the office".
"It's just one of them things. We are learning some new things. Sometimes it works, sometimes it doesn't. Unfortunately today it didn't work," he said.
"We've got a fair while to work on things now ahead of the outdoors. I am going back to Australia tomorrow, so heading back there to work... and sort things out."
Four medals for Great Britain
The US won gold in the men's and women's 4x400m relays to draw the championships to a close and leave the Americans top of the medal table with 16 (six gold, four silver and six bronze).
A total of 32 nations medalled, with Great Britain's team of 11 finishing fourth in the table with two golds, one silver and one bronze.
Gold
Men's 60m: Jeremiah Azu
Women's 400m: Amber Anning
Silver
Men's 1500m: Neil Gourley
Bronze
Women's 1500m: Georgia Hunter Bell