Reigning champion Serena Williams is one match away from another appearance in the final of the Australian Open after beating Maria Sharapova in the quarter-finals in Melbourne.

The world number one has now defeated her Russian rival 18 times in a row after securing a 6-4 6-1 victory on Rod Laver Arena.

Williams, who will meet fourth seed Agnieszka Radwanska in the last four, did not have things her own way in the opening set against Sharapova after going 2-0 behind, while she also needed attention from the tournament doctor after the first set.

However, the six-time champion Down Under, 34, powered away in the second set to wrap up victory in an hour and 32 minutes and remain on track as she looks to retain her title.

“It was super intense,” said Williams. “She’s an incredibly intense and focused player who was world number one. When you’re playing someone so great you have to come out with a lot of fire and intensity.

“I’ve been playing this whole week aggressive and I don’t think I started out playing that way. At the start of the second set I wanted to play the way I have been doing to get to the quarter-finals.”

Williams is 1.13 to beat Radwanska (5.50) on Thursday after the 26-year-old Pole proved to be too strong for 20th seed Carla Suarez-Navarro, winning 6-1 6-3.