Ana Ivanovic 'broke a spell' to post a magical win over Serena Williams in the fourth round of the Australian Open.
Ivanovic had never won a set against Williams in four previous meetings while the world number one went into the clash on a 25-match winning run and as the huge title favourite.
But Ivanovic fought back from a set down to win 4-6 6-3 6-2 to thunderous applause from Rod Laver Arena. She will play Canadian teenager Eugenie Bouchard, who came from a set down to knock out Casey Dellacqua, the last Australian singles hope.
Bouchard, 19, is seeded for the first time at a grand slam and will rise again from her current ranking of 31 after a 6-7 (5/7) 6-2 6-0 victory that again demonstrated what an excellent match player she is despite her tender years.
26-year-old Ivanovic reached the Australian Open final in 2008 and followed up by winning her maiden grand slam title at the French Open the same year to become world number one.
Great things were predicted but the weight of expectation was too much for Ivanovic at such a young age and she had managed only one more grand slam quarter-final.
This was without question her best grand slam victory since winning Roland Garros, and she was nerveless serving it out to love.
She said: "I actually believed. I had some confidence coming into today's match. I really did certain things extremely well and I kept her under pressure, I felt, throughout the whole match.
"I just stayed in the moment physically. I didn't think much about the occasion and who I was playing, because it can get overwhelming.
"I had to break a spell, fourth round, and what better place to do it than here against such a champion?
"I feel I'm different person and player now, and I enjoy it much more. Maybe these years make me appreciate much more these kind of wins."
Despite winning the first set, Williams was clearly not at her best right from the start and revealed afterwards that she almost withdrew from the tournament with a back problem.
She said: "I almost pulled out. I'm such a competitor. I probably should have.
"I feel she played unbelievable today. I think she went for her shots.
"It's not like I gave her the match. I tried to fight the best I could. At least I feel good that I tried the best that I could on this day.
"I know for a fact I can play so much better than what I did today so, knowing that, I'm not disappointed."
Williams suffered the problem in practice before her third-round match against Daniela Hantuchova and her movement was not good enough to cope with sustained excellence from Ivanovic.
She stressed she did not want to take credit away from her opponent, but said: "I made a tremendous amount of errors, shots I haven't missed since the 80s."
It is the third year in a row that physical problems have contributed to shock exits for Williams at the Australian Open, with ankle injuries hindering her against Ekaterina Makarova in 2012 and Sloane Stephens last year.
She said: "I have won this tournament five times. I think I have done pretty well here.
"I feel like I'll win it again. Obviously not this year, but maybe next year."
Williams' coach Patrick Mouratoglou had said prior to the tournament he thought she could win all four grand slams this year, but the American said: "I gave up on that a long time ago.
"Maybe I can win four in a row, but it seems like in the one year it's kind of difficult for me for whatever reason."
"I really did certain things extremely well and I kept her under pressure" - Ana Ivanovic
Fourth seed Li Na had saved a match point in her third-round win over Lucie Safarova but was on top form in routing Makarova 6-2 6-0 in less than an hour on Saturday.
That is sure to have pleased coach Carlos Rodriguez, with Li saying: "Yesterday I did a lot of practice because I really made Carlos sad with my match two days ago.
"At least today I think I made him a little bit happier. I feel much better."
Li is also happy that her next opponent, Flavia Pennetta, is older than her, even if just by a day.
The 31-year-old Italian reached her second successive grand slam quarter-final with a 6-1 4-6 7-5 win over ninth seed Angelique Kerber.
Pennetta missed the Australian Open last year following wrist surgery and feared she may have to sit out again after problems with the same wrist earlier this month.
Instead, she is through to her first ever grand slam quarter-final outside New York.