Serena Williams produced her most impressive performance of this year's Australian Open to beat Dominika Cibulkova 6-2 6-2 in a dominant quarter-final display.

The world number one had appeared sluggish at the start of matches in earlier rounds, but she immediately caused problems for Cibulkova, whose nervy start on serve was punished when she was broken in the third game.

Winners continued to arrive with apparent ease for Williams, and she made another breakthrough in the fifth game to pile further pressure on Cibulkova.

Last year's finalist was unable to produce a response as Williams eased to success with four aces in the final game of the opening set.

A couple of errors from Cibulkova appeared to be the beginning of the end as Williams broke at the start of the second set.

Cibulkova, who has never beaten her American rival, had a chance to keep the match alive with a couple of break points in the fourth game, but the 11th seed failed to capitalise on a rare opportunity.

Williams refused to open the door again, and the top seed continued her fine display by finding another break to wrap up the win comfortably and set up a meeting with Madison Keys, who recorded victory over Venus Williams earlier in the day,