Ana Ivanovic upsets Serena Williams in fourth round at Australian Open

Ana Ivanovic stunned Serena Williams in the Round of 16. (Quinn Rooney/Getty Images)

MELBOURNE, Australia -- No. 14 Ana Ivanovic stunned five-time champion Serena Williams 4-6, 6-3, 6-3 in the fourth round of the Australian Open on Sunday.

In a controlled performance against the No. 1 seed, Ivanovic cast aside the demons that have plagued her since ascending to the top of the game nearly six years ago when she won her one and only major, at the 2008 French Open. A Grand Slam champion and world No. 1 at just 20, Ivanovic never again played with the freedom and joy that got her there. The pressure and expectations were crippling for the shy Serb, who wanted nothing more than to escape the spotlight and attention. Turns out, she didn't exactly like toiling away in tennis' dark and lonely shadows either.

"I was in a little bit not the best place in my mind," Ivanovic said after the match. "2010 was a little bit hard in the beginning. But you just keep fighting because this is what I love to do and this is what I'm best at. I still am so young and I deserve a better chance and a better shot at it."

Unless you were paying close attention, little foreshadowed this result. Sure, Ivanovic was undefeated in 2014 after winning a lead-up tournament in Auckland, New Zealand, two weeks ago for her first title since 2011. The 26-year-old had also been playing fantastic offensive tennis, as showcased by her three-set win over No. 17 Samantha Stosur in the third round. She hit 46 winners to Stosur's 21, with 31 from her powerful forehand. And if you looked closely during her post-match interviews, there was a calmness surrounding Ivanovic. Her victories weren't leaving her over the moon. They made her believe she could do it again.

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Ivanovic's win over Williams was a triumph in both execution and psychology. She smacked 33 winners, including 20 on the forehand side. How many forehand winners did Williams hit? Only two. (In fact, 13 Williams' 22 winners overall were aces.) For years, Ivanovic has played with an air of desperation. She has squandered big leads over top opponents because of nerves. In the past, her incessant fist-pumping after every point was a sign of insecurity, a woman who needed to remind herself after every point that, yes, she could win.

So even with a break lead early in the final set, an Ivanovic victory seemed far off. She was on a roll in every facet of the game, swatting return winners off Williams' second serve and stepping in to control as many rallies as possible with her forehand. There would be no wobble this time: Ivanovic held her final two service games at love. For a player who has struggled with her serve over the years, Ivanovic faced just three break points in the match, all in the first set. Williams went nine consecutive games without earning a break point.

Ivanovic beat Williams for the first time in five attempts, snapped the 17-time major champion's 25-match winning streak and advanced to the quarterfinals of the Australian Open for the first time since 2008.

"There were moments in the match where it could have gone either way," Ivanovic said. "I could have just made few more errors. But I really just believed in my game and stepped up when I needed to. I had to break a spell -- fourth round -- and what's the better place to do it than here against such a champion?"

Of course, the big elephant in the room when discussing Ivanovic's powerful display is the health of Williams' back, which she injured before her third-round match against Daniela Hantuchova. While Serena was coy about the injury, coach Patrick Mouratoglou revealed that the pain was so bad that Williams almost withdrew before playing Hantuchova.

“I don't know how she won against Hantuchova because it was 10 times worse than today," Mouratoglou said. "Today was a combination of not being able to move like she usually moves and was in bad positions, but also the fact that Ana played a great match."

Williams also complimented Ivanovic while lamenting her own play.

"I made a tremendous amount of errors, shots I missed I normally don't miss; I haven't missed since the '80s," Williams said. "I'm always disappointed when I lose, but it's always a good thing. I plan on getting better. It's almost good that I lost because now I know what to work on.

"Maybe I wasn't the best physically, but that had nothing to do with it. Ana just played a really good match. She did what it takes to win."

Ivanovic credits her new Serbian team for her recent spate of positive thinking and belief. After years of high-profile coaches, including Sven Groeneveld, Heinz Gunthard  and Nigel Sears, she brought in a new team and the end of last year, headed by coach Nemanja Kontic.

"Sometimes a coach can look good on paper," Ivanovic said earlier in the week. "But when you team up with someone, it doesn't work out that way. I really tried to also listen to a lot of people's advice. It wasn't always the right choice. I made some mistakes because of this."

The decision to go with a less "brand name" coaching team seems to have signaled a desire for Ivanovic to take control of her own career. There is also undoubtedly less pressure for her to perform at her best all the time to earn her coach's respect.

"In the past, I've been listening too much to what people are saying, what they thought was good for me," Ivanovic said. "I didn't really listen to my inner instincts or what my gut was telling me. This time I really thought, This is my career and I have to turn toward me and just see what works out for me. I made that decision. I didn't regret it for one moment."

Kontic may not have much of an established résumé, but it turns out he's been exactly what she needed. One of the biggest benefits of the coaching change has been the ease with which Ivanovic can now communicate her feelings. Though Ivanovic communicates almost flawlessly in English, never underestimate the power of shared culture and language, especially when building a relationship founded on trust.

"There is no secret," Ivanovic said. "Every country has its own mentality, its own way to see things and to do things. We can really understand each other with less words. Even when I'm in doubt, I can express myself better and they can answer me better."

Ivanovic will play No. 30 Eugenie Bouchard in the quarterfinals.