Birmingham: World number one Wang Yihan crashed to a shock defeat in the All-England Open final as her compatriot Li Xuerui snatched the famous title 21-13, 21-19 here on Sunday.
Li was seeded only seventh and far less experienced, but winning the German Open last week seemed to have increased her self-assurance, and she continued in the same confident vein to grab a career-best win.
"This is my greatest win and it is very important to me," Li said.
"It's a famous title, and different from the other Super Series. I want to take it step by step but I may become world number four after this."
"I felt confident about winning," said Wang, who had won the All-England Open title three years ago and the world title only seven months ago.
"And I really hoped to be the winner."
The 21-year-old Li began well, moving the shuttle around well and showing a sharp eye for openings when she had manoeuvred them.
Li also made a remarkable recovery from 5-13 and 10-15 down in the second game as Wang began to flag.
But hers was a strangely error-strewn performance in the first game and then an unexpectedly flat one emotionally when she seemed likely to win the second game.
Wang may have been affected by her quarter-final efforts when she had had to save four match points against the twice former champion Tine Baun, and then to survive an 89-minute match - the longest of the tournament - in her semi-final with the defending champion Wang Shixian.
Her start to the final was surprisingly uncertain.
She was soon 3-7 and clearly making more errors than she expected.
Once when she retrieved the shuttle too high to the net, enabling Li to kill it comfortably and advance to 9-4, Wang turned her head away in disappointment.
And when she punched a return of serve too long on the next point, she turned her whole body away in dissatisfaction. Six points later she went to the side of the court to put some tape round a finger.
There were moments of Wang brilliance, as during a fierce flat exchange two points before the end of the game, which made the crowd gasp, but she concluded it with another error.
It did however signal what she could do.
And in the second game she began to do it much better. Wang's clears were deeper and her attacks better selected, and at the interval she was already nine points ahead.
But at 13-5 there was a bad sign, when she seemed uncharacteristically slow to reach a push to the net, and then two points later Wang laboured ominously to make a hairpin shot at the net.
Li, moving better than her famous opponent, made rapid progress after that, closing an eight-point deficit to two, and then perhaps taking encouragement from Wang's emotional body language in a tight finish.
The top seed again turned away in frustration as she put a fast overhead drop into the net at 18-16, and winced after dominating a brilliant flat mid-court exchange, only to miss the opening she created.
Wang never won another point. It was quickly 18-18, and on her first match point Li showed admirable calm during a thrilling climactic rally at the end of which Wang put a round-the head clear wide.
Li's career-best win and improved ranking also increases China's chances of getting a maximum three singles players into the Olympic Games later in the year.