Christine Ohurougu edged out defending champion and pre-race favourite Amantle Montsho by the slimmest of margins to win World championship Gold in a new British record of 49.41.
The Newham and Essex Beagles athlete is known for her sprint finish but even the most loyal of fans must have been worried with around 30 metres to go.
The 2008 Olympic champion produced a truly remarkable display, out dipping the Botswana athlete as well as breaking Cathy Cook’s 29 year national record.
It is an extraordinary achievement for an athlete who could only manage a silver medal at last year’s home Olympics.
Ohurougu was almost lost for words as she spoke to BBC Sport after her victory.
"I can't believe I've done that, it feels like a dream. It is what I have been working towards all season," she said.
"It was so tight on the line and I was so desperate to win it. I just wanted my name to come up.
"The last couple of days have been really tough and I just want to thank everyone who helped me. It feels really surreal and strange, it doesn't feel like I'm really here.
"I was thinking do what you can, just get over the line. The icing on the cake is the national record, that's all I wanted.
"Whatever you want just go for it, I am really happy I kept believing and trusting in what I could do."
Ohurougu surely now must be heralded as one of Britain’s greatest ever female athletes following her breathtaking race in Moscow.
The gold is Great Britain's second of the World Championships after Mo Farah claimed victory in the men's 10,000 metres on the opening day.
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