Third round result:

S Williams (US) v N Petrova (Rus)

1-6 7-5 6-3

* denotes server

By Caroline Cheese

Third set

Williams 1-6 7-5 6-3 Petrova
And that's it. Williams knocks out the fifth seed and in doing so, proves herself as a genuine title contender.

Williams 1-6 7-5 5-3 Petrova
Now we'll see what Williams is made of as Petrova holds to 30 to leave the American to serve for it.

Williams 1-6 7-5 5-2 Petrova
Gritty again from Williams. She, along with most of the crowd, is stunned when Petrova challenges a call - and even more stunned when the replay proves the Russian right. What would have been 40-15 quickly becomes 30-30 but the former champion produces two crushing points to move to within a game of the fourth round.

Williams 1-6 7-5 4-2 Petrova
Bad Petrova is back, missing too many first serves and putting pressure on herself. She can't do anything about the last point though, Williams threading a fabulous backhand down the line.

Williams 1-6 7-5 3-2 Petrova
Right, I'm not going to make any more bold statements about who's in control. Williams grits her teeth and holds quite easily. Mum Oracene allows herself a smile. Well, in fact, she has been smiling happily throughout this match...

Williams 1-6 7-5 2-2 Petrova
It must be some kind of magic racquet because all of a sudden, Petrova is in control - banging down her 10th ace to draw level.

Williams 1-6 7-5 2-1 Petrova
Petrova is furious with herself as she misses a forehand and decides a change of racquet is in order. Williams is understandably none too happy about the delay and glares at her opponent. Her mood is hardly helped when she drops the break.

Williams 1-6 7-5 2-0 Petrova
Petrova slaps a forehand into the net and Williams has now taken six games in a row. You have to sit back and admire the way the American simply refuses to give in.

Williams 1-6 7-5 1-0 Petrova
The break doesn't upset Williams' concentration and she holds to 15. Needless to say, Petrova must hold now and stop the rot.

Second set

Williams 1-6 7-5 Petrova
Drama on Rod Laver Arena... Petrova challenges on a second serve, but she's wrong and the double fault leaves her facing two set points. The Russian saves the first with a drop shot, which sends Williams tumbling, but the American picks herself up and takes the set when Petrova double-faults again. The fifth seed heads off court for a 'comfort break'.

Williams 1-6 6-5 Petrova
And now it's Serena on a roll - three games in a row and the American must now be favourite to take this set. Petrova is not much more than a bystander in the match at the moment, waiting to see what Williams will come up with next.

Williams 1-6 5-5 Petrova
Serena comes out fighting and wins the warm applause of the Rod Laver Arena crowd. Petrova doesn't do too much wrong but Williams takes a few risks and she's back on track.

Williams 1-6 4-5 Petrova
Typical Williams. She digs deep and produces a battling service game to put the pressure on Petrova. Can the Russian deliver?

Williams 1-6 3-5 Petrova
Before this match, I mentioned Petrova's lack of nerve... well, there's no sign of it. She nonchalantly places an angled volley just over the net on the first point and goes on to hold to 15.

Williams 1-6 3-4 Petrova
It's all gone wrong for Serena. Could her lack of matches be catching up with her? A tired-looking double fault makes it 0-30 and Petrova breaks to love to make it four games in a row.

Williams 1-6 3-3 Petrova
Petrova applied some hairspray during that changeover - that won't do anything for the feminist cause. She's quickly back to crunching down aces though and we're level again.

Williams 1-6 3-2 Petrova
Cracking stuff. Williams surprises everyone by reaching a drop shot but can't do anything about the reply and faces a break point. She saves it with some stunning counter-punching but she eventually cracks and this is now a truly absorbing match.

Williams 1-6 3-1 Petrova
Petrova has her thigh injury re-taped during the changeover. She doesn't seem too bothered by the injury but Williams is proving very annoying at the moment. The American is beginning to look like the Williams of old. The fifth seed does well to hang on from break point down.

Williams 1-6 3-0 Petrova
Not nerves from Serena surely? She starts the game with a double fault and slips to 15-40 but the American is showing all her fighting qualities out there and she hangs on.

Williams 1-6 2-0 Petrova
Williams finally gets onto a Petrova serve and smacks away the return - delivering a death stare at the Russian for good measure. A stunning rally on break point ends with Petrova netting a drop shot and suddenly Williams is in this.

Williams 1-6 1-0 Petrova
Petrova produces the shot of the match so far, a lovely angled volley off a fiercely-hit dipping forehand from Williams. The American comes through from deuce though.

First set

Williams 1-6 Petrova
Three brutal aces in a row from 15-0 take Petrova to the opening set and the Russian is cruising. Serena looks bemused by the whole thing.

Williams 1-5 Petrova
OK, some stats to back up that last statement... Serena has managed five winners and 15 errors. She had a 40-0 lead in this game and let it slip. Not good. Credit to Petrova though - she's moving much better than her opponent.

Williams 1-4 Petrova
You get about one winner to every three errors at the moment from Serena and it ain't going to get the job done against the number five seed. The Russian holds to 30.

Williams 1-3 Petrova
Two horrible backhand errors from Serena to start the game and then a mishit forehand. Petrova passed up two break point chances last time around but she's gifted the break now as Serena floats a forehand wide.

Williams 1-2 Petrova
The roof is over Rod Laver Arena - not because it is raining, you understand, but because it might rain. You wouldn't find that sort of negative thinking at Wimbledon... but then, of course, you wouldn't find a roof either. Comfortable for Petrova.

Williams 1-1 Petrova
Williams produces a woefully short second serve at 15-30 and Petrova smacks it down the line to take control of the point. Williams saves one break point with an ace and the second with a crunching forehand.

Williams 0-1 Petrova
Hardly a convincing start from Petrova, who double-faults to give Serena a sniff at 30-30 but the Russian is helped by a slew of errors from her opponent.

Williams is now ranked 81 in the world but the ever-confident 25-year-old has still been talking up her title chances and this match will be a true test of her credentials.

Petrova, meanwhile, is a solid performer but is almost as injury-prone as her opponent and sometimes lacks nerve on the big occasion.