MELBOURNE (REUTERS) - Reigning champion Serena Williams ramped up the power to beat fifth seed Maria Sharapova 6-4, 6-1 and reach the semi-finals of the Australian Open on Tuesday.
It was her 18th victory in a row over the Russian.
Sharapova broke the world No.1 in the first game and mounted a stiff challenge in the opening set but wilted in the second to extend a losing record against Williams that goes back 12 years.
The 34-year-old American, who twice had treatment during breaks in the rematch of last year's final, has reached the last four at Melbourne Park on six previous occasions and gone on to win the title every time.
Williams, who is looking for her 22nd singles Grand Slam title, has an 8-0 head-to-head record against her semi-final opponent Agnieszka Radwanska.
Radwanska advanced to her second semi-final at Melbourne Park with a 6-1, 6-3 victory over 10th seed Carla Suarez Navarro.
Said the fourth seed after her win: "I knew it would be a tough one. She is very solid, like most Spanish players and I knew everything would come back to my side. I tried to be aggressive and focus on my serve and I think I did a good job."