Hello and welcome to LIVE coverage from this fourth round clash between world number one Serena Williams, five-times a former champion in Melbourne, and Ana Ivanovic, who was runner-up at Melbourne Park in 2008.

Here we go then. The players are just about ready to go; Ivanovic jogging out to the baseline, Williams wandering nonchalantly. It will be Williams to get the clash underway by serving first ...

It's fairly cloudy out and about in Melbourne today but just about perfect tennis weather. The current temperature is 20 degrees and there is the odd bit of sun poking out from behind the light and fluffy white clouds.

Ivanovic makes her way out on to court looking pretty calm and collected. Williams also looks pretty comfortable as she makes her way out with her pink Beatz headphones on. Pink to match the rest of her outfit.

There has been talk that Serena Williams has been struggling a little with a troublesome back injury but that, as yet, is just rumour.

ROUTE THROUGH - To get to this stage of the tournament, Williams has overcome Australian Ashleigh Barty, Serbia's Vesna Dolonc and Daniela Hantuchova all in straight sets. Ivanovic, meanwhile, has beaten Kiki Bertens and Annika Beck in straight sets before having to recover from a set down to beat 17th seed and home hope Sam Stosur in the third round.

STATS - These two have met each other, surprisingly, only four times before. Worryingly for the Ivanovic camp, though, she has never won a match against Serena. The world number one has taken victory in each of those four previous encounters. In fact, even worse than that, Ivanovic has never even taken a set off Williams.