Two-time Olympic champion Faith Kipyegon of Kenya took gold in 3:52.96, with Ethiopia's Gudaf Tsegay second.

"It was all about the medal - I took my time but I am so happy I got it," the Scot told BBC Sport.

Olympic silver medallist Muir had come close to a world medal before, having finished fifth, fourth and fifth again in her last three outings.

"This time last year I did not have any global outdoor medals and now I have two," the 29-year-old said.

"This was the one that was really bugging me.

"After I got the Olympic silver I was like 'this is the year, I am going to get it' and I have. I am so pleased."

It is Great Britain's first medal of these championships.

'That was an extra level'

Laura Muir (left) has now won Olympic silver and World Championship bronze in the 1500m

Muir admitted she arrived in Oregon low on confidence but laid down her marker with a strong semi-final performance earlier this week.

She was in the mix from the very start of the race, initially as part of a breakaway alongside Kipyegon, Tsegay and Hirut Meshesha.

With Kipyegon and Tsegay jostling at the front, Muir stuck with them as Meshesha dropped with two laps to go.

After crossing the line, Muir lay on the track for some time before collecting her medal and congratulating her opponents.

"I didn't look at the clock - I was like I am not looking because it won't be good," she joked.

"I am not surprised it felt that painful because it was so fast. That was an extra level."

Muir suffered a stress reaction to her femur in her right leg in February and was unable to train for two months.

"It was the longest I have had off from running," she added.

"It was always going to be tight but I had a lot of faith in my coach and physio. Between the two of them and me just working my butt off in training, we got there."

'The gutsiest runner I know'

Laura Muir will compete for Scotland at the Commonwealth Games later this month

Muir and Kipyegon joined together for a lap of honour, with Muir saying the crowds were special after the Tokyo Games were held behind closed doors.

She was also cheered on by her parents, who saw her win a medal at a global championship in person for the first time.

Former marathon runner Paula Radcliffe said she had seen Muir "dig deeper than she ever had before" to ensure she was on the podium in Oregon.

"She is the gutsiest runner I know out there. Every reserve has come out and she was not letting go," Radcliffe said on BBC TV.

"I think the Laura Muir we have seen this year is a calmer, more serene, more in control Laura, despite the problems she has had.

"I think this will bring her on another level in terms of that confidence, and knowing what she's capable of."