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.

So it is Cibulkova through to the quarter-finals where she will face either world number one Serena Williams or 24th seed Garbine Muguruza, who play next on the Rod Laver Arena. A great run through the draw from Victoria Azarenka though, unseeded after injury almost completely wiped out her 2014 season. The former world number one is very much on her way back to the top echelons of the game.

Cibulkova 6-2 3-6 6-3 Azarenka. Game, set and match. So, so impressive from last year's runner-up Cibulkova as she earns herself a first match point with another huge return that Azarenka can only net in return. And one match is all it takes for Cibulkova to wrap up the win, a slightly tired looking Azarenka netting another forehand to concede interest in the match.

Cibulkova 6-2 3-6 5-3 Azarenka. A fantastically aggressive return from Azarenka draws the reply long from Cibulkova and draws the scores level at deuce. The Slovak sneaks ahead again with a forehand winner down the line to bring herself a game point to consolidate the break. Sensational point from both players, utilising the whole of the court, all the angles and hitting the fluff off the ball. In the end though it is Cibulkova who comes out on top, riffling off another cross court forehand passing shot winner. Azarenka will have to serve to keep this match alive now.

Cibulkova 6-2 3-6 4-3 Azarenka. Break. A fourth ace from Azarenka comes at just the right time as it earns her a game point from 30-all. She can't take advantage of it, pulling up on a forehand and dumping the ball into the net. A perfect drop shot from Cibulkova then brings up yet another break point and sure enough the Slovak's got it, a series of brutal backhands across court eventually over-stretching Azarenka who can only net her backhand.

Cibulkova 6-2 3-6 3-3 Azarenka. Another battling service game but Cibulkova comes out on top with an incredible display of strength, crounching down to a low ball on the run and flicking it down the line, okay not for a winner but with enough pace and low enough that Azarenka can do nothing with it by the time it reaches her.

Cibulkova 6-2 3-6 2-3 Azarenka. Azarenka has to work really hard to stop Cibulkova from running away with the game as the Slovak produces another two huge forehand winners to go 0-30 up against the Azarenka serve. A couple of missed returns let the Belarusian back into the game although Cibulkova levels at deuce with a huge forehand that Azarenka can only return long down the centre of the court. The Slovak launches herself at a forehand approach shot, doing enough to push Azarenka into the defensive forehand into the net and earn herself another break point. But it goes begging with a netted forehand return from the Cibulkova. A second break point also goes begging for the Slovak and Azarenka goes on to hold with a forehand across court followed by an inside out forehand winner across court. Great hold for the Belarusian in an eight minute plus game.

Cibulkova 6-2 3-6 2-2 Azarenka. Fantastic length from Azarenka helps her earn herself break point. But sensational defence again from Cibulkova saves it, the Slovak eventually turning defence in to attack with a backhand passing shot winner down the line off the stop volley from Azarenka. And Cibulkova goes on to hold with a couple of huge serves, sandwiching a forehand winner from the Slovak.

Cibulkova 6-2 3-6 1-2 Azarenka. Break. Cibulkova is well in the tramlines when she flicks her raquet at a forehand with incredible strength for a winner down the line. Azarenka did nothing wrong in that point and yet finds herself having lost it! Cibulkova gives a weaker second serve from Azarenka the treatment, slapping it away for a forehand winner down the line, to bring up a break back point. She can't quite take advantage of it, pulling a cross court forehand just wide while attempting the passing shot. Azarenka saves a second break point with a cross court backhand approach shot winner but the Belarusian can do nothing about a third, Cibulkova standing up and belting a backhand winner down the line. The initial call is out but the umpire corrects it and Azarenka doesn't bother to challenge. We are back on serve in this final set.

Cibulkova 6-2 3-6 0-2 Azarenka. Break. Azarenka is finding the open spaces now, while CIbulkova gets a warning for receiving coaching from her players box. Cibulkova attempts the forehand passing shot down the line only to be cut off by Azarenka with a backhand volley. The Slovak attempts the opposite direction but pulls her forehand wide across court and it's three more break points for Azarenka. She only needs the one though doing enough damage with a running forehand across court that Cibulkova can only net in reply.

Cibulkova 6-2 3-6 0-1 Azarenka. A good start from Azarenka for this third set as she holds for the loss of just the one point with back-to-back solid serves, both of which Cibulkova cannot return in play.

Cibulkova 6-2 3-6 Azarenka. Set. A stunning drop shot from Cibulkova is matched only by Azarenka's ridiculous pick up and flicked forehand drop shot winner in reply. Azarenka earns herself another set point with a brutal forehand that catches the top of the tape and rolls over. And this time the Belarusian does force the deciding set, going back behind Cibulkova enough that the Slovak is off balance when she hits her low backhand into the bottom of the net.

Cibulkova 6-2 3-5 Azarenka. Break. Sensational defence from Cibulkova as she hangs in the rally far longer than she has any right too. But in the end Azarenka works her way into the net and finds a forehand drive volley winner. A smash winner on the next point and it's two set points for the Belarusian. A double fault squanders the first while great defence from Cibulkova denies Azarenka on the second, the Belarusian again ending up on the floor after a slip on her final shot. From there Cibulkova earns herself a break back point. She can't take the first one, going long with a forehand, but threads a backhand passing shot down the line for a winner to earn a second and this time she does get one of the breaks back, Azarenka going long with a forehand down the centre of the court. Cibulkova will still have to serve to keep this second set alive, though.

Cibulkova 6-2 2-5 Azarenka. Winners number 45 and 46 are in quick succession, the first from Cibulkova (a forehand down the line) and the next from Azarenka (a backhand volley down the line) but it is the Slovak, who takes the game without too much trouble. Cibulkova holds to 15 when fails to land her forehand return in court. The Belarusian will have the chance to serve out the second set after the change of ends, though.

Cibulkova 6-2 1-5 Azarenka. Another hugely competitive point marks a change in tone from Azarenka's squeals. But she manages to stick with Cibulkova in the rally before turning defence into offence with a forehand winner down the line, Back-to-back netted forehands from Azarenka lets Cibulkova back into the game and put the pressure on the Belarusian at 40-30. But Cibulkova goes long with her forehand return and the Slovak will now have to serve to stay in this second set.

Cibulkova 6-2 1-4 Azarenka. Break. Big trouble now for Cibulkova in this second set as she nets an off-balance forehand to gift Azarenka three more break points. And this time it is the Slovak's turn to slap down a double fault to concede her serve.

Cibulkova 6-2 1-3 Azarenka. Azarenka breaks the pattern of the opening as she riffles a forehand drive volley across court for a winner to bring up two game points before maintaining her break advantage with a trip into the net after a lengthy rally and finds a fantastic backhand volley winner deep down the line.

Cibulkova 6-2 1-2 Azarenka. A forehand winner down the line from Azarenka to trail 30-15 on the Cibulkova serve is the 33rd winner of the match - Azarenka's 10th, while Cibulkova has hit 22. This is massively high quality tennis. Cibulkova gets her second set off the mark when Azarenka fails to land her forehand back in play.

Cibulkova 6-2 0-2 Azarenka. A love service hold from Azarenka, again reproducing the start of the match, to consolidate the break. The Belarusian gets a little lucky to get away with a drop shot, Cibulkova just slipping as she gets up to the ball with Azarenka on hand to put away the easy volley on her way to the hold.

Cibulkova 6-2 0-1 Azarenka. Break. Just like she did in the first game of the match, Azarenka breaks for the opening game of the second set. The Belarusian takes a leaf out of Cibulkova's book in that game, taking the ball earlier and trying to rush her opponent. The Slovak manages just one point, riffling a forehand passing shot winner down the line, but can do nothing to stop the onslaught from Azarenka, who finds a forehand winner down the line of her own to bring up break points before sealing it with some more aggressive play.

Cibulkova 6-2 Azarenka. Set. Cibulkova is seeing the ball as if its a football at the moment, taking a step to her right and rattling a forehand return of serve winner across the court off a very decent first serve from Azarenka. The Slovak follows that up by doing exactly the same thing off the opposite wing on the next point. She then brings up three set points with another exceptional rally, firing a forehand approach shot winner down the line. Azarenka saves the first with a body serve that Cibulkova can only net in return an then the second with a serve down the centre of the court followed up by a forehand drive volley winner down the line. But a second double from the Belarusian hands the set to Cibulkova. Since going 2-0 up, Azarenka has been completely outplayed.