What a shot that is from Simona Halep. Just after the disappointment of missing the chance to take the set she rushes to the net and then whips a shoulder-high forehand volley over the net, swinging the racket like a lasso. That brings up another set point.

This time no mistake. The world number one shows all her experience to take the opener.

A clench of the fist from Simona Halep. I said she had to find another level and she has. The Romanian top seed smacks a big backhand down the line to bring up 30-30.

Now Osaka goes into the tramlines. Set point to Halep.

Roger Federer is in a sunny mood after a rapid win in what was his first day match of the tournament.

Asked if there are any differences from playing at night, he said: "I was considering sunglasses and a towel for the beach but, no, the only thing is the racquet strings are a bit tighter to help control the ball, but it's not crazy hot today.

"Other than at I just had to set my alarm at a different time. It's a different rhythm playing in the day and not going to bed at 3am.

"We might go out for dinner tonight but Mirka has left already - she must have other plans!"

Image source, EPA

Image source, EPA

A first sign of real frustration from Osaka as she misses again. She must be wondering how she didn't get ahead early on in this set. She shakes her head as a forehand loops over the baseline to give Halep another game.

Osaka's coach nods in support from the stands but it's Halep who is a game away from the opener.

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

There was something about that second point - I don't know what it was - but you could tell the break was coming.

Halep strikes and she has shown all of her experience here. Osaka looked the better player in the early exchanges but failed to take her chances. Halep cuts out the mistakes on the big points and Osaka hits for forehand into the tramlines. First blood to the world number one.

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

Simona has looked more focused in this match than we sometimes see. She seems really relaxed and looks to be enjoying it out there. She isn't focused out of an anger or frustration.

Here comes the world number one.

All of Osaka's big shots had landed until this game but, as Halep just keeps the ball in play, they start to fail.

Two break points for Simona Halep.

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

This is a very competitive game, with both players hitting aggressively from the ground.

Naomi Osaka is a bundle of energy. She's bobbing around and then slapping her thigh in disappointment as she misses the chance to break. That was a real tough hold for Halep with four six deuces.

If Simona Halep didn't know she'd be in a battle this evening she will now. Osaka is playing outstanding tennis, pummelling her way through the world number one's defence. "Come on!" the youngster screams as she brings up a second break point of the game.

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

You don't see Halep at the net so often but she closed it perfectly there to make a nice volley.

Osaka has got herself right in another Halep service game as she fights her way to 30-30.

Halep needs to find a bit more here. That's better. She gets on the front foot and finishes a point at the net.

The world number one goes wide next point though. Deuce.

Two break points for Roger Federer over on Rod Laver Arena.

The defending champion only needs one, as Marton Fucsovics sends a backhand long to give the Swiss a second break in the third set.

He's on the home straight. Tomas Berdych awaits in the quarter-finals.

Naomi Osaka continues to impress. She names Serena Williams as her idol and, while I'm not going to say she is at that level, there are a few similarities.

The hair is the most obvious but there's also a bit of Serena in her big serve and heavy-hitting groundstrokes. The Japanese player holds to love.

The shade is gradually making its way across the court with just half a service box and the tramlines in day light. A little tricky for the players?

As Jill Craybas says the importance of Halep's serve is clear. When she doesn't quite manage one of her quickest or most accurate efforts, Osaka looks to get on the attack straight away.

It's working as well. The youngster brings up break point...

Halep sees it off. Just.

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

Halep's serve is so important. Her second serve can be vulnerable so she needs to get plenty of strong first serves in.

As yet I haven't sign one sign of sluggishness from Simona Halep. She has spent over three hours more time on court than her younger opponent but comes out on top of a lung-busting early rally.

Osaka responds well. really well. She pummels a few more groundstrokes with her big, bushy ponytail flowing behind her.

Excellent start from the youngster.

Naomi Osaka has started very well in this match. She pounds a few winners in her own service game and then goes on the attack on Halep's serve.

The 20-year-old is highly-rated and is the youngest player left in the draw in Melbourne, playing in her first Slam quarter-final. No sign of nerves early.

Osaka pushes well but Halep holds onto her serve. A game each to start us off.