Christine Ohuruogu said her body had gone "through a war" after she won the 400m to became the first British woman to win two World Championship titles.
The 29-year-old broke Kathy Cook's British record, set when Ohuruogu was two-and-a-half months old, as she beat reigning champion Amantle Montsho by four thousandths of a second.
She said: "I knew it would be Montsho on the line, that's what I predicted.
"I knew it must be about experience and holding my nerve."
The London 2012 silver medallist won the 2007 World and the 2008 Olympic titles in similar fashion by passing her rivals in the closing stages.
But she revealed she won in Moscow despite failing to follow pre-race instructions.
"[As I was running for the line] I just remember thinking: 'My coach is going to kill me'," she added as she dedicated her victory to her coach, Lloyd Cowan.
"He gave me specific instructions, but I never listen. But I never panic. The race isn't won until you cross the line. I knew I had to throw myself at the line, I knew it was going to be tight."
Botswana's Montsho led for most of the race but failed to dip for the line, giving Ohuruogu, making a late charge on her inside, the opportunity to snatch victory.
Only computers could separate the two as pre-race favourite Montsho, 30, and Ohuruogu both finished in 49.41 seconds.
On closer inspection, the British team captain was deemed the winner by the finest of margins, crossing the line in 49.404 with her rival a fraction behind in 49.408.
"That must be the fifth championship final I have been to, so I know what I am doing," she said, adding that she thought her experience would give her a significant advantage over her rivals.
"I thought I could safely bet that they would not know how to safely manage the final - and I know I'm a lot stronger," continued Ohuruogu.
"My body has gone through war, so I kind of had that on my side. And I knew that I was brave enough to challenge if I had to."
It was Cook's British record, though, set at the 1984 Los Angeles Olympics, rather than the world title, that was Ohuruogu's main target ahead of the championships.
"It is really special because I got my national record," she said after breaking Cook's record by two hundredths of a second.
"That's what I've been working for all season. It's been a passion of mine because I had everything else. Winning is a bonus."
Ohuruogu, who will also race in the 4x400m relay in Moscow, did not realise she had won and revealed she was the one who broke the news to Montsho.
"I didn't realise how far behind I was, but I knew in the last 50m the others would start dying," she continued.
"When I crossed the line, I just thanked God that I had finished.
"We didn't know what was happening. I heard the crowd screaming and was thinking: 'Do I really want to see what happened?'
"Montsho didn't know I'd won and asked me what had happened. I didn't want her to find out like that."