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Kei Nishikori

Williams beats Sharapova; Djokovic, Federer to meet in semis

Serena Williams has never lost in the semifinals of the Australian Open. Neither has Novak Djokovic.

A key difference between the defending champions is that Williams beat the most-experienced and highest-ranked challenger in her half of the draw when she extended her streak to 18 consecutive wins against Maria Sharapova with a 6-4, 6-1 quarterfinal victory on Tuesday.

Williams said she wasn't aware that she had won the Australian Open all six previous times she won her quarterfinal match, "but that's good."

"It's not a stat that's set in stone," Williams said. "I still have to win two matches."

Five-time champion Djokovic, after...