Former world number one Ana Ivanovic held her nerve to pull off a massive upset and beat injured top seed Serena Williams on Sunday in the Australian Open fourth round.
The Serb came from a set down to win 4-6, 6-3, 6-3, ending the American's bid to match Chris Evert and Martina Navratilova with 18 Grand Slam titles.
Williams, who was gunning for a sixth Australian crown, revealed afterwards that she had a back injury and had almost withdrew from the tournament before her third-round clash with Daniela Hantochova.
"I almost pulled out. I'm such a competitor. I mean, I probably should have," she said, without giving specific details on the injury. But she refused to blame the problem for her defeat. "I made a tremendous amount of errors, shots I missed I normally don't miss, I haven't missed since the '80s. I'm just not used to missing those shots.
"I think Ana just played a really good match. She did what it takes to win."
Williams, whose movement was clearly restricted, pulled out of the doubles on Friday, although the withdrawal was blamed on an injury to sister Venus.
It was a major scalp for Ivanovic, 26, and set up a quarter-final against either Canadian teenager Eugenie Bouchard or local hope Casey Dellacqua.
"She's such a great player. Going on to the court today, I really just tried to give my best," said the Serb, who is on a hot run of form after winning the Auckland International this month. "I tried to make it a good match. I was very competitive till the last moment, and I'm just very thrilled, obviously."
Since winning at Roland Garros in 2008, Ivanovic, ranked 14, has only made a Grand Slam quarter-final once before, at the 2012 US Open. But under new coach Nemanja Kontic, the Serb has been thriving. Ivanovic said she tried hard not be daunted by Williams, considered by many to be the best female player ever.
"It's hard. I had to remind myself all the time just to stay in the moment," she said. "Because there were moments in the match where it could have gone either way."
She ultimately ground down Williams with her sizzling groundstrokes and self-belief for her first win against the American in five encounters.
Despite the shock loss, Williams set a new record by appearing in her 70th match at the Australian Open, surpassing the previous record held by Lindsay Davenport.
Williams, 32, started with two double faults, helping Ivanovic to three break point chances, but she saved them all and regrouped.
Williams blasted through her next service game and Ivanovic, who is popular with Australian fans and nicknamed "Aussie Ana", rallied from two points down in the next to hold.
The Serb was moving well and a cross-court forehand gave her a break point and she grabbed the chance. But her advantage didn't last with Williams immediately levelling. Williams held to be 4-3 in front, yelling "C'mon!", and turned up the heat to take the set.
The second set went to serve until the fifth game when Ivanovic worked her way to two break points. Williams saved one with a towering serve but she lost the other.
For the third Williams serve in a row, Ivanovic worked her way to break points and while the American again saved two, she couldn't stop a raking forehand winner on the third.
Williams was being worn down and the Serb scored a big break to go 2-0 in front in the third set.
The despondent American was broken again and Ivanovic served to love for a famous win.
