A powerful forehand winner from Sam Stosur gets her off to a good start in this service game, and Heather Watson can only find the net on the next point.

The Brit has the former US Open champion running though and after two Watson volleys it's the Australian who goes long and follows up with a double fault.

Image source, AP

Sam Stosur looks shaken, but she manages to claw a point back on Heather Watson's serve with a deep return.

But that's as good as it gets for the Australian, who lets out a frustrated cry as Watson opens up a three-game lead.

Heather Watson now has two break points after surviving that opening service game, and what a shot that is to break Sam Stosur.

Scuttling back towards her own baseline she digs out a fantastic forehand winner down the line to leave Stosur sprawling and take the opening break in this set.

All eyes on Heather Watson then, with four out of five Brits through can the 24-year-old add to the list?

She's gone to a third set against Australian Sam Stosur, a former US Open champion, and is having to fight to hold onto her opening service game in the final set.

And that is a big hold from the Brit. A powerful backhand into the body of Stosur means the Australian can't pick it up over the net.

A big, big break from British number two Kyle Edmund over on Court 5 - he's two sets up against Colombia's Santiago Giraldo and is now serving for the match.

Heather Watson loses the second set and this one is going to go the distance.

Sam Stosur took an early break and managed to hold on, including through that 11-minute game at 4-2 in the Australian's favour.

Rafa Nadal has broken Florian Mayer in the third set and will now have the chance to serve for the set, and the match, on the Rod Laver Arena.

The Spaniard looks to be on his way into the second round.

That was a mammoth game between Heather Watson and Sam Stosur that topped 10 minutes. 

Eventually the Australian held on, and remains with the break in this second set.

Image source, Getty Images

Heather Watson gets a break point opportunity in the second set, but Sam Stosur holds to bring it back to deuce and momentarily maintain her advantage in this set.

Stosur catches the top of the net and watches the ball agonisingly drop onto her side of the net for another break point in Watson's favour, but it's saved again and draws a chorus of applause from the Melbourne crowd.

I said it looked like Santiago Giraldo was getting frustrated, well now he's gone and smashed his racquet on the floor in a furious rage after sending a backhand off target.

It's the sort of move every amateur player has considered when inevitably hitting a wayward shot, before realising we don't have a stash of spares to dip in to.

Giraldo trades his twisted metal for a new set of strings, but he stills trails by two sets to Kyle Edmund.

Santiago Giraldo is growing increasingly frustrated in his match with Britain's Kyle Edmund.

Edmund has a two-set lead and earns two break points on his opponent's service game, but he can't take them for the moment. 

A bit of a let off really for Giraldo, who almost looked to have given up on the point before Edmund went long with a forehand. However, it's the Colombian who holds.

Back on the Margaret Court Arena, Heather Watson is a set up but still behind in this second set after a little flurry from home favourite Sam Stosur.

The former US Open champion capitulated in the first after leading 2-0, but broke Watson early in the second.

The crowd are getting a little bit edgy every time the Australian makes a mistake though, she edges one off the frame of her racquet and that brings groans from the Melbourne faithful.

Kyle Edmund couldn't capitalise on a set point a moment ago, but now he has three to play with.

And the British number two only needs the one - he moves two sets up on Colombia's Santiago Giraldo. Impressive stuff from the 22-year-old.

David Law
Radio 5 live sports extra commentator

Kyle Edmund is hoping he won't have a turnaround to endure. He did have a set point but couldn't take it.

You feel like it is a big set for him, so he doesn't have to extend the match too long in these oppressive conditions.

Kyle Edmund has a set point on Court 5 - but the British number two can't take it.

He's forced wide by Santiago Giraldo's crosscourt forehand and can only respond with a shot into the net.

Colombian Giraldo holds on for the minute, but Edmund still leads by a set.

Well the second set on the Margaret Court Arena has started in the same fashion as the first, with Sam Stosur going two games up.

Heather Watson fought back to win the last set, but she's a break down again in the second.

Rafa Nadal has only needed to convert two of his 10 break points in this match to build a two-set lead.

The Spaniard is storming through against Germany's Florian Mayer at the minute and is looking back on form - he's hit 27 winners and made 76% of first serves so far today.