Serena Williams losing to Ekaterina Makarova was a big surprise.

Caroline Wozniacki falling in the quarterfinals, to Kim Clijsters no less, is anything but.

The world's No. 1 player will no longer be the world's No. 1 player.

Wozniacki has only advanced beyond the quarterfinals in a Grand Slam twice in her career. At the age of 21, she is still relatively young, but it is quickly becoming commonplace to see her bounced before truly meaningful tennis in a major event.

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She might as well have been the underdog in her quarterfinals clash with the defending Australian Open champion.

Wozniacki didn't just lose either, she didn't even capture a set.

She fought hard in the second set, but ultimately fell 6-3, 7-6 (7-4) to the elder Clijsters.

The Belgian looks to be on a mission to defend her title.

Despite an injury in an Aussie Open tune-up, she's been one of the best down in Melbourne Park and has defeated three straight ranked opponents including two top five seeds—Wozniacki and Li Na.

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Now she'll take on third-seeded Victoria Azarenka in the semifinals.

Azarenka has been tough so far and rallied after dropping the first set in the quarterfinals to defeat her first ranked opponent of the tournament, No. 8 Agnieszka Radwanska, 6-7 (0-7), 6-0, 6-2.

She'll pose a test for Clijsters, and the Belgian holds a 4-2 career record over the Belarusian.

The point here is that, once again, Wozniacki is an afterthought in a Grand Slam event. Clijsters, meanwhile, continues to her mission.