Christine Ohuruogu led a shock British one-two in the women's 400m at the World Championships.
Nicola Sanders took silver in a thrilling final few yards, the British pair overhauling long-time leader Novlene Williams.
The win is a sensational end to a year of heartache for Ohuruogu.
Osaka is her first major meeting since returning from a 12-month ban handed down for missing three out-of-competition drug tests.
She crossed the line in 49.61secs with Sanders second in 49.65, just a hundreth of a second ahead of Williams.
Ohuruogu insisted her success was just reward for the hard work put in during her ban, which only expired three weeks ago.
"It was very hard,'' she admitted on BBC2.
"But I am very proud of myself because I had operations on both legs, I trained, got up every day and did my work.
"I trained hard, always with the World Championships in mind.
"It (winning) was all a dream, you hope you would, but to have gone and done it...''
Ohuruogu hopes her rivalry with Sanders will help to set the standard for a new era of British athletics.
"It was very close,'' she said of the race.
"It is very good in terms of competition, it's what Britain needs right now, people competing at the top level.
"I hope that people take a leaf out of that.''
The new champion will now be able to pay off her estimated £20,000 legal bill - racked up fighting her suspension - with the prize money earned in Osaka.
Sanders, who like Ohuruogu ran a personal best, admitted afterwards she had not been sure of her position as she crossed the line.
"I had to just convince myself and just concentrate on my own race,'' she told BBC2.
"I didn't have a clue what had happened, I just lunged for the line.''
She added: "It's awesome, you can't ask for more. It's fantastic.'' Christine Ohuruogu led a shock British one-two in the women's 400m at the World Championships.
Nicola Sanders took silver in a thrilling finish which saw the British pair overhaul long-time leader Novlene Williams in the final few yards.
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