Jordyn Wieber won women's all-around gold as another World Gymnastics final went down to the wire in Tokyo.
Russia's Victoria Komova could not overhaul the American with her final score, finishing 0.033 marks behind her fellow 16-year-old.
Hannah Whelan finished ninth, an impressive result for the Briton and a considerable improvement on her 16th-place finish last year.
"I'm really happy to have improved so much," Whelan, 19, told BBC Sport.
"I had a good competition and I was happy with my vault - I don't think I've ever stuck a vault dead before. As this week has gone on, the pressure has been less and less. Today was a case of going out to enjoy it."
Whelan's result is the third best in British women's gymnastics history, and the best since Beth Tweddle's eighth place at the World Championships in 2006.
Liverpudlian Whelan underlined her credentials as GB's strongest female all-around gymnast but Wieber and Komova, the latest products of the world-leading gymnastics industries that are the United States and Russia, currently operate at a level above most others.
Not that they are immune to errors, some of which helped Thursday's contest develop into the second successive thriller after China's narrow victory in Wednesday's men's team final.
Youth Olympic champion Komova struggled on the beam while Wieber's main error, which came on the bars, looked to have cost her the gold medal.
The Russian seemed certain to be crowned champion as she finished her floor routine, but a score of just 14.333 drew gasps from the crowd, elation from Wieber, and only silver for Komova.
"I was so surprised. I had a mistake on bars and I didn't think it was enough," the American, already a team gold medallist this week, told BBC Sport.
"This is so important for London 2012. This was my first world championships, I had high expectations for myself and I'm so happy."
None of last year's all-around medallists took part in this year's final which, despite injury accounting for some absences, indicates the pace of change in the sport as the fight for Olympic places hots up.
Komova must contend with the return from injury of compatriot Aliya Mustafina, 2010's dominant gymnast, and Wieber faces competition from an array of Americans, not least Beijing veterans Nastia Liukin and Shawn Johnson, both of whom have now announced comebacks.
For the time being, Wieber will take on Komova in three further individual apparatus finals over the weekend - the bars, beam and floor - and the pair are expected to challenge for medals in all three.
"Five golds would be a dream come true," said Wieber.
Ninth is an excellent result for Whelan, who improved markedly on her 2010 displays on three of the four pieces of apparatus.
She believes the top eight is well within her grasp at the Olympic Games, but must improve on bars (where she scored just 13.258 here, with others in the high 14s and beyond) to stand a chance.
"Bars is one of my weak pieces so I'll definitely go back and work on that," she said.
Wieber's winning all-around score was 59.382, ahead of Komova's 59.349. China's Yao Jinnan took bronze with 58.598 and Whelan scored 56.124.
Three British chances for medals remain, beginning with Dan Purvis in the men's all-around final on Friday.
Purvis, 20, is one of British Gymnastics' lesser-known successes and has a genuine chance of an Olympic medal in 2012 if he continues to progress.
He finished fifth in last year's world all-around final in Rotterdam, less than a mark outside the medals, and has once again squeezed into the lead group of the top six qualifiers this year.
Louis Smith follows Purvis in Saturday's pommel horse final, but told BBC Sport he has yet to decide whether to play it safe or attempt his hardest routine - the most difficult in the world.
"I really want to do my hardest routine in the final but my coach isn't too sure," said Smith.
"My coach says if I do my normal routine, I'm guaranteed a medal. But I'm not looking at it like that, I'm looking at what I need to do at 2012 to get a gold medal and that's to do my hardest routine.
"There's no better time to do it than a world championship final."
Beth Tweddle completes the triumvirate in Sunday's floor final, a title she won in London two years ago.
Tweddle cannot defend her uneven bars world title after errors in qualifying saw her fail to progress, but she compensated for that with a superb bars routine in Tuesday's team final, as Britain came fifth to record their best-ever finish.
The 26-year-old said she was keen to "prove a point" ahead of the Olympics and will look to do the same on Sunday.