Big serve, big forehand winner to follow.

Wozniacki rediscovers some of the strokes that saw her take a 3-0 lead in the final.

She holds to love.

Wozniacki waltzes around a midcourt return to take it on the forehand side, but Halep keeps it alive.

The Dane goes high into the Melbourne sky in response and eventually watches Halep go wide with the 19th shot of the rally.

Another overcooked backhand from Halep and that's 30-0.

Pat Cash
Former Wimbledon champion on BBC Radio 5 live sports extra

Halep is starting to come up with some really good shots. Wozniacki is a counter-puncher. She is the sort of player who makes you beat yourself - if you don't play well, you lose.

Halep has to keep this going all match though because Wozniacki doesn't tire.

Image source, EPA

Simona Halep is on a roll now, she's finding good depth with her ground strokes and even a first ace - right on the line.

Another follows. The Romanian certainly has her eye in.

Wozniacki pops a return long. And that's a whistle-stop hold to love.

Now it's Wozniacki on the run, pounding the earth beyond the baseline.

The Dane looks to coax a slice in response, but that misses - Simona Halep breaks back.

Just wide from Simona Halep on the backhand side, but the Romanian was forced to run and run by Caroline Wozniacki.

The Dane saves the first break back point, and then serves her first ace of this final.

Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra

Halep is doing a good job but Wozniacki looks a little bit on edge because of nerves.

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Paul Staveley: Wozniacki’s come out with a hell of a game face on. Halep looks nervy. The first 3 games of the next set are going to be crucial. Could get away from Halep if she’s not careful.

That's long... three break points Halep.

Caroline Wozniacki, how're your nerves?

A wobbly forehand gives Simona Halep a route into this service game, and a misjudged net dash and weak volley makes it 0-30.

Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra

This is where Wozniacki can start to get a little bit nervous. She really needs to stay mentally tough to serve this out.

Wozniacki digs in and pulls it back to 30-30.

Halep is putting everything into every point, and again she takes control with a leaping winner at the net.

A punchy serve follows, and she holds.

Russell Fuller
BBC tennis correspondent at Melbourne Park

Halep needs to land more first serves in. Only 53% of first serves are going in whereas 71% are going in for Wozniacki.

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Wonderful, aggressive tennis from Halep. She just toys with Wozniacki, pushing the Dane wide before coaxing a volley into the space left behind.

Wozniacki dashes to the net on the next point, but that's some passing shot from the Romanian and the world number two can't get strings to it - 30-15.

Simona Halep finds herself having to serve to stay in this first set.

The world number one took a little while to warm up on Rod Laver Arena.

Image source, Getty Images

Wozniacki takes a moment to compose herself on serve, that ball toss wasn't quite right.

She gives out a little "come on" after taking the point with some fierce forehand play from the baseline.

Brilliant! Best rally of the match - that 17-shot exchange had everything, a deft Halep slice, a Wozniacki volley and finally a net-cracker from the Romanian.

But Wozniacki holds.

Ooo. Halep clips the net with her return and it throws Wozniacki off, sending a wild forehand towards the line judges.

Halep cracks the net again, but this time it trickles down the tape on her side - 15-15.

Simona Halep, who doesn't have a clothes sponsor despite being world number one, is fighting out of the red corner in this winner-takes-it-all final - although that dress may be more orange... my eyes.

Anyway, without getting into a whole 'white-gold dress-style' debate, the Romanian seamlessly makes her way to 30-0 with some aggressive strokes and then picks out the best of the lot with a flying forehand winner from midcourt.

Another love hold. That's more like it.

Image source, Reuters

Wozniacki almost walks to the changeover before hearing her first serve called long... and then double faults.

The Dane screeches across court to meet a Halep exchange and it's the Romanian who eventually goes long.

Wozniacki holds.

Not sure what Halep was looking for there - a long, looping forehand that just sails harmlessly beyond Wozniacki.

The world number one then pops a backhand into the tramlines, and Wozniacki is just proving a little too punchy to handle - 40-0.