Hello and welcome to LIVE coverage from the first of today's women's fourth round matches where the unseeded but two-times former winner Victoria Azarenka takes on 11th seed Dominika Cibulkova for a place in the last eight.

Cibulkova 5-2 Azarenka. Azarenka is right up on the baseline and fires a double handed backhand return of serve across court for a winner that flashes back past Cibulkova before the Slovak has properly finished her service motion. Cibulkova manages to save it with a smash and forehand drive volley winner. She then goes on to hold with a booming forehand winner down the line and an ace down the centre of the court. Five straight games for Cibulkova and Azarenka will have to serve to stay in this opening set after the change of ends.

Cibulkova 4-2 Azarenka. Break. Another blistering forehand winner from Cibulkova brings up another break point. Azarenka saves it with a service winner but the Slovak will get a second chance after rattling an inside-out forehand winne across court. And this time the pressure gets to be too much for Azarenka as she slaps down her first double fault of the match.

Cibulkova 3-2 Azarenka. A second love service hold in quick succession from Cibulkova, who has totally settled into the match now. The Slovak rattles a forehand winner down the line, out of reach of Azarenka, to wrap up the hold, her third game in a row. Big game coming up for Azarenka after the change of ends.

Cibulkova 2-2 Azarenka. Break. The Slovak opens with two wrong-footing winners, one off either wing, going back behind Azarenka, before going down the centre of the court and asking Azarenka to create her own angle. The Belarusian nets her off-backhand and it's two break back points to Cibulkova. The Slovak only needs the one, however, as she again peppers the baseline and draws the netted forehand from Azarenka. Back on serve in this opening set.

Cibulkova 1-2 Azarenka. Cibulkova gets her side of the scoreboard ticking over a little belatedly but with a love service hold, sealing the game with a dipping cross court forehand passing shot that Azarenka can only frame towards the crowd - even with her superior wingspan.

Cibulkova 0-2 Azarenka. The Belrusian races through a love service hold, including her first ace. Worrying times for the Cibulkova camp.

Cibulkova 0-1 Azarenka. Break. Believe it or not, Cibulkova is actually the harder hitting of these two and so playing with the roof closed should benefit her marginally more than Azarenka. Nonetheless the Slovak finds herself facing two early break points. She saves the first with a forehand bullet down the line and the second with a backhand winner down the line. Azarenka denies Cibulkova on a couple of game points, including one 17-stroke rally, before earning herself another break point with a cross court backhand that the Belarusian gets down low to to flick over the net. And this time she does break, a forehand approach shot doing the trick. A seven minute opening game!

The warm-up over and done with and Azarenka already has the trainer on court. It's only for a plaster for her finger though. The players are ready to go and it will be Cibulkova to begin by serving first...

We are starting the day with the roof closed. It just 14 degrees in Melbourne today with rain forecast throughout the morning. So the organisers have taken the decision to just close the roof before play even starts.

These two have faced each other nine times before with Azarenka leading the head-to-heads by a whopping seven wins to two. Cibulkova did win both of their most recent clashes, although they have not met since 2012 and one of them was in a walkover. Azarenka has never lost to Cibulkova when they've played on a hard court.