Williams gets her footwork all wrong again and her forehand return goes long. 0-15.

The American tries to lightly touch a back-hand volley over the net but it loops all over the shop and it goes wide. 0-30.

And the crowd go wild again as Kerber wins an outstanding rally - easily the longest of the game so far.

The German stays at the baseline smacks an unstoppable forehand winner. 0-40 and three break points.

And the seventh seed has done it! She's 2-0 up in the third. Wow, wow, wow. 

Kerber wins the first point to huge cheers from the crowd. 

The German smacks a diagonal ace to make it 40-0. She's making this look easy.

But Williams responds by slipping and sliding across court and hits an angled forehand winner into the left-hand tram line.

Kerber's going nowhere, though. She screeches with delight as she pummels a straight forehand down court to hold her service game.

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Both players go off for a comfort break, and perhaps this will provide a bit of thinking time.

Kerber keeps the American waiting for a while. Bit of mind games there? Or just a queue for the ladies?

In my experience, probably the latter.

Williams takes a 30-15 lead with an ace of 116mph. Woosh.

Two set points after Kerber hits a return over the baseline. And Williams levels the match! 

Still not a vintage Serena performance, but she's back in the contest. 

We're going all the way...

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Kerber serving to stay in the second set.

The 27-year-old challenges a call but her shot is millimeters off the baseline, and Williams goes 0-15 ahead.

And the American steals another point as Kerber comes steaming across the back of the court to reach a Williams lob, but she can't get her return over.

But the German is not deterred. She recovers from 0-30 down and holds her serve with a super forehand into the bottom corner. 

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Williams wins a grunt-filled rally and serves a lovely ace to waltz into the lead.

Will she take the game to love? Not on Kerber's watch...

The German composes herself and brings it to 40-30. 

But with Kerber stranded at the back of the court after a stretching return, Williams rushes towards the net and dinks the ball over to win the game.

Williams challenges Kerber's serve at 15-15 but it just sneaks in at the corner. Daggers emerge from the eyes of the American. 

Kerber stays stuck to the baseline and, after another terrific serve followed by a sweet forehand winner, the left-hander holds her service game. 

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Just as Williams thinks she's getting somewhere, Kerber finds some magic.

The German leaps like a gazelle and hits a beautiful forehand winner. It's 0-30.

The American finally serves an ace - her first of the match - and recovers to hold her serve.

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The Taylor Swift classic "Shake It Off" booms out during a short break at the Rod Laver Arena. Inspiration for Williams perhaps? 

It seems to have worked. The American goes into a 0-40 lead after two double faults and an error from Kerber. Three break points.

The German saves the first with a forehand winner, and Williams gets her footwork wrong and Kerber saves another. One to go...

Second serve for the seventh seed and the pair enter a powerful rally. Kerber hits long and Williams breaks! 

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Kerber is really punishing Williams' second serve. The German earns herself a mini fist pump as she places a beautifully accurate back-hand into the corner for 30-15.

Williams composes herself and her improving forehand takes it to 40-30. She replicates the same shot to win the game. 

Did we doubt Kerber's serve before this match? Maybe, but she's just smacked one so hard, Williams' return escaped out the arena.

The number one seed recovers to level 30-30, but in comes another whopping Kerber serve - over 100mph this time.

The German levels in style.

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Kerber continues as she left off, and snatches the first point off Williams' serve. 

The American's footwork is still troubling her, but she gains some confidence with a couple of decent forehand winners and takes four consecutive points to hold her serve.

And not a peep out of Williams. Maybe quiet and composed is the way forward now?

Image source, Reuters

Leon Smith
Great Britain Davis Cup captain

"It's absolutely deserved, what a brave performance this has been so far from Kerber. You would never know this is her first Grand Slam final. Credit to her and her coaching team - they have come up with a perfect game plan."

Kerber is flourishing here. The German seventh seed takes a 40-0 lead as Williams hits into the net for a second time. 

Three set points. And she only needs one go! 

Williams drops a set for the first time in the tournament.

Kerber does a little air punch in celebration. Is a shock on the cards?

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The shoulder shrug is back, but for the wrong reasons. Williams over-hits a volley and goes 0-15 down. She glance at her mum in the crowd, hoping for some inspiration.

...OUCH. What was that?

I don't think words can do justice as to how loud Williams just shrieked after a back-hand winner. Only dogs could hear her.

It worked, though. Williams holds her serve. Kerber now goes for the set. 

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Williams shrugs her shoulders when a forehand return beats Kerber, as if to say: "why can't I do that all the time?". 

The German remains unflappable so far, and takes the game to 15. 

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A double fault from Williams and we're at 15-15. She's just not at the races so far.

Kerber's forehand return is so much stronger and more accurate and it earns her another break point.

She wins it! A huge miss from Williams. Two breaks to Kerber now and she's playing very well. 

Image source, EPA

Leon Smith
Great Britain Davis Cup captain

"Kerber has started to miss a too few many first serves, dipping towards the 50% mark, which is not where you want to be against Serena."

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Kerber is looking calm, composed and confident.

The seventh seed loses the first point on her serve but is returning well on the forehand, unlike her opponent who lets out a piercing scream as she hits long again. 

A wound-up Williams manages to take the game to deuce and, on the advantage, thumps an accurate forehand winner to break.

We're level. 

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Williams loses the first two points on her serve - she just can't get her returns to fall within the perimeter. 

A well-executed back-hand volley at the net leads to the first shout of "C'MON" from the number one seed. It's 15-30.

Kerber takes the game to deuce, but a light tap over the net gives Williams the advantage and the lady in yellow sees out her service game. 

Image source, AFP