Serena Williams wins 18th straight match against Maria Sharapova at AO

Serena Williams of the US hits a shot during her quarter-final match against Russia's Maria Sharapova at the Australian Open tennis tournament at Melbourne Park, Australia, Jan 26, 2016. [Photo/Agencies]

MELBOURNE - World No 1 Serena Williams has sent a strong message to the rest of the Australian Open field, brushing aside a challenge from 5th seed Maria Sharapova in little over an hour and a half when they met in their quarterfinal on Tuesday.

In what was their 21st meeting on the tour, Sharapova looked to break a string of 17 straight defeats to the American when she broke early in the match to take a 2-0 lead.

But Williams - a six-time Australian Open champion - fought hard to regain parity after the Russian secured the early break, then broke again on her way to take a hard-fought, hour-long first set, 6-4.

The world No. 1 then found another gear in the second, cruising to the 6-4, 6-1 victory on Rod Laver Arena.

After the win, Williams said the match was full of fight despite the lopsided scoreline.

"It was super intense. She is an incredibly intense, focused player," Williams said of Sharapova post-match."

"When you're playing someone like that you have to come out with your own fire and intensity."

The No. 1 seed said she was feeling fresh and healthy heading into her semi-final against Agnieszka Radwanksa on Thursday.

Williams added that she didn't feel any pressure on herself to win a seventh Australian Open title, but admitted a roadblock in Radwanska could shake things up, saying the No. 4 seed has one of the best defensive games on the tour.

"She is a great defender and I think it will be a great match. I'm going to do my best, I have nothing to lose," Williams said on Tuesday.

The pair will face off in Melbourne on Thursday.